diff --git a/.gitattributes b/.gitattributes
index 1ff2de7..7434425 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -2,3 +2,10 @@ fw/aic8800D80/*.txt text eol=lf
 fw/aic8800D80/*.bin binary
 fw/aic8800DC/*.txt text eol=lf
 fw/aic8800DC/*.bin binary
+/.gitattributes text eol=lf
+drivers/aic8800/aic_zlp_quirk/*.c text eol=lf
+drivers/aic8800/aic_zlp_quirk/Makefile text eol=lf
+tests/issue63-zlp-quirk/*.conf text eol=lf
+tests/issue63-zlp-quirk/*.md text eol=lf
+tests/issue63-zlp-quirk/*.sh text eol=lf
+tests/issue63-zlp-quirk/Makefile text eol=lf
diff --git a/INSTALL_SCRIPT.md b/INSTALL_SCRIPT.md
index 9eda17c..8ed3c41 100644
--- a/INSTALL_SCRIPT.md
+++ b/INSTALL_SCRIPT.md
@@ -2,12 +2,19 @@
 
 ## Overview
 
-This automated installation script (`install.sh`) simplifies the process of installing the AIC8800D80 WiFi driver on Linux systems.
+This automated installation script (`install.sh`) installs the AIC8800 Wi-Fi
+driver and firmware loader on Linux systems. Wi-Fi/Bluetooth combo adapters use
+the standard kernel `btusb` driver after firmware initialization. For USB
+device `368b:8d81`, it also installs a device-scoped ACL bulk TX ZLP companion
+module without replacing the distribution's `btusb.ko`.
 
 - Automatic Secure Boot detection
 - Automatic dependency installation
 - Automatic driver compilation and installation
 - Automatic module loading on boot
+- Automatic cleanup of obsolete `aic_btusb` configuration
+- Automatic `aic_zlp_quirk` handling for the validated `368b:8d81` device
+- Wi-Fi-only and Wi-Fi/Bluetooth combo adapter support from the same branch
 - Comprehensive error handling
 - Colored output and logging
 - Compatible with Ubuntu, Debian, Fedora, and derivatives (DKMS supported `dkms.conf`)
@@ -37,4 +44,4 @@ This script is used to diagnose build issues with the AIC8800D80 driver. Useful
 ```bash
 # Make the script executable and run it
 chmod +x diagnostic_build.sh && sudo ./diagnostic_build.sh
-```
\ No newline at end of file
+```
diff --git a/README.md b/README.md
index 47f9694..9fdcc2a 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# AIC8800 Linux Driver
+# AIC8800 Linux Wi-Fi and Bluetooth Driver
 This driver supports AIC8800-family chipsets used by devices such as the Tenda U11, AX913B, and TP-Link Archer TX1U Nano.
 
 > **Legacy MCU revision 1 branch:** You are viewing `legacy-mcu1`. This branch
@@ -12,14 +12,26 @@ This driver supports AIC8800-family chipsets used by devices such as the Tenda U
 > `chip_mcu_id=0` hardware or when the MCU revision is unknown. See the
 > [D80](tests/issue58-mcu1-legacy-fw/README.md) and
 > [DC/DW](tests/issue71-mcu1-v3-profile/README.md) support notes before installing.
+>
+> After switching branches, rerun `sudo ./install.sh` and reboot; switching the
+> Git branch alone does not replace firmware already installed under
+> `/lib/firmware`.
 
 Added support for devices with Vendor ID 368B (tested).
 
 Tested on Linux kernel 6.16 with Ubuntu 25.04 and 6.1.0.27 with Debian 12.
 
-> **Bluetooth support:** This branch initializes the integrated Bluetooth
-> controller for the kernel's standard `btusb` driver. It does not contain or
-> install `aic_btusb`.
+The same driver supports Wi-Fi-only adapters and Wi-Fi/Bluetooth combo
+adapters. On combo devices, `aic_load_fw` uploads the AIC firmware and the
+standard Linux `btusb` driver handles the Bluetooth HCI interface. The obsolete
+custom `aic_btusb` module is not used.
+
+USB device `368b:8d81` also uses the bundled `aic_zlp_quirk` companion module.
+It adds the Bluetooth ACL bulk TX zero-length-packet behavior validated in
+[issue #63](https://github.com/shenmintao/aic8800d80/issues/63), while leaving
+the distribution's original `btusb.ko` installed and bound to the device. The
+quirk is filtered to that VID:PID and fails closed when the required kernel
+probe support is unavailable.
 
 > [!NOTE]
 > **Bluetooth branch retirement:** Do not switch MCU1 hardware to the separate
@@ -44,18 +56,18 @@ Before installing the driver, delete all aic8800-related folders under /lib/firm
 #### Method 2: Manual Installation
 
 #### Copy udev rules:
-Copy the aic.rules file to /lib/udev/rules.d/:
+Copy the aic.rules file to /usr/lib/udev/rules.d/:
 
 ```bash
-sudo cp aic.rules /lib/udev/rules.d/
+sudo cp aic.rules /usr/lib/udev/rules.d/
 ```
 
 #### Copy firmware:
 
-Copy the aic8800D80 folder from ./fw to /lib/firmware/:
+Copy the firmware directories from `./fw` to `/lib/firmware/`:
 
 ```bash
-sudo cp -r ./fw/aic8800D80 /lib/firmware/
+sudo cp -r ./fw/aic8800* /lib/firmware/
 ```
 #### Navigate to the driver directory:
 
@@ -122,3 +134,52 @@ If the device is still not active, check the kernel logs for any errors related
 sudo dmesg
 ```
 
+### Bluetooth on Combo Adapters
+
+Bluetooth support does not require a separate AIC transport module. After
+`aic_load_fw` initializes a combo adapter, the kernel automatically binds its
+Bluetooth interface to `btusb`. A Wi-Fi-only adapter does not expose that
+interface, so the Bluetooth path remains inactive.
+
+Verify the expected modules and controller with:
+
+```bash
+lsmod | grep -E 'aic_load_fw|aic8800_fdrv|aic_zlp_quirk|btusb'
+lsusb -t
+bluetoothctl list
+```
+
+To scan after a controller appears:
+
+```bash
+bluetoothctl
+power on
+scan on
+```
+
+If Bluetooth is missing or reports HCI timeouts, run the read-only diagnostic
+script and attach its output together with the current boot log:
+
+```bash
+chmod +x diagnose_bt.sh
+sudo ./diagnose_bt.sh
+sudo journalctl -k -b --no-pager
+```
+
+The installer removes active references to the retired `aic_btusb` integration.
+It does not force-load `btusb` or globally change the Bluetooth rfkill state;
+normal kernel device matching and the user's system policy remain in control.
+
+For `368b:8d81`, verify the ZLP hook and its injection counter while Bluetooth
+traffic is active:
+
+```bash
+cat /sys/module/aic_zlp_quirk/parameters/hook
+cat /sys/module/aic_zlp_quirk/parameters/injections
+```
+
+The Wi-Fi-reset recovery behavior tracked in
+[issue #53](https://github.com/shenmintao/aic8800d80/issues/53) remains a known
+limitation: after an airplane-mode or hotspot reset, Bluetooth may require a
+physical unplug/replug of the adapter.
+
diff --git a/aic.rules b/aic.rules
index ac85c00..31820c3 100644
--- a/aic.rules
+++ b/aic.rules
@@ -1,3 +1,4 @@
+# AIC8800 USB mass-storage mode switch rules
 KERNEL=="sd*", ATTRS{idVendor}=="a69c", ATTRS{idProduct}=="5721",  SYMLINK+="aicudisk", RUN+="/usr/bin/eject /dev/%k"
 KERNEL=="sd*", ATTRS{idVendor}=="a69c", ATTRS{idProduct}=="5723",  SYMLINK+="tendaudisk", RUN+="/usr/bin/eject /dev/%k"
 KERNEL=="sd*", ATTRS{idVendor}=="a69c", ATTRS{idProduct}=="5724",  SYMLINK+="ugreenax900", RUN+="/usr/bin/eject /dev/%k"
@@ -7,3 +8,6 @@ KERNEL=="sd*", ATTRS{idVendor}=="a69c", ATTRS{idProduct}=="5727",  SYMLINK+="ten
 KERNEL=="sd*", ATTRS{idVendor}=="a69c", ATTRS{idProduct}=="572a",  SYMLINK+="tendaudiskv5", RUN+="/usr/bin/eject /dev/%k"
 KERNEL=="sd*", ATTRS{idVendor}=="a69c", ATTRS{idProduct}=="572c",  SYMLINK+="cudydiskv2", RUN+="/usr/bin/eject /dev/%k"
 KERNEL=="sd*", ATTRS{idVendor}=="a69c", ATTRS{idProduct}=="572f",  SYMLINK+="aicudisk572f", RUN+="/usr/bin/eject /dev/%k"
+
+# AIC8800D80 "Pandora" clone: switch 1111:1111 to its operational USB ID.
+ACTION=="add", SUBSYSTEM=="usb", ATTR{idVendor}=="1111", ATTR{idProduct}=="1111", RUN+="/bin/sh -c 'if [ -x /usr/sbin/usb_modeswitch ]; then exec /usr/sbin/usb_modeswitch -c /etc/usb_modeswitch.d/1111:1111; elif [ -x /usr/bin/usb_modeswitch ]; then exec /usr/bin/usb_modeswitch -c /etc/usb_modeswitch.d/1111:1111; fi'"
diff --git a/bazzite/README.md b/bazzite/README.md
index 9b572b0..6efd2b0 100644
--- a/bazzite/README.md
+++ b/bazzite/README.md
@@ -56,7 +56,11 @@ sudo rpm-ostree install "$rpm_path"
 sudo systemctl reboot
 ~~~
 
-After reboot, the Wi-Fi module and firmware loader will be available.
+After reboot, the Wi-Fi module and firmware loader will be available. On combo
+adapters, Bluetooth is handled by the standard `btusb` kernel module after
+firmware initialization. USB device `368b:8d81` also autoloads the packaged
+`aic_zlp_quirk` companion module for its required Bluetooth ACL bulk TX zero
+packet behavior; the distribution's `btusb` module is not replaced.
 
 This RPM is built for the kernel reported by `uname -r`. Rebuild and reinstall
 it after a Bazzite kernel upgrade.
diff --git a/bazzite/aic8800d80.spec b/bazzite/aic8800d80.spec
index 62c6ec1..4284101 100644
--- a/bazzite/aic8800d80.spec
+++ b/bazzite/aic8800d80.spec
@@ -1,11 +1,11 @@
-%global commit d10bc52903f30a45e49777fd8254765403c9eb64
+%global commit 51b7b6e72989afe4d21f52e55b70f5a4d6b21e5b
 %global shortcommit %(echo %{commit} | cut -c1-7)
 %{!?kver:%global kver %(uname -r)}
 
 Name:           aic8800d80
 Version:        %{shortcommit}
 Release:        1%{?dist}
-Summary:        AIC8800D80 USB Wi-Fi driver
+Summary:        AIC8800 USB Wi-Fi, Bluetooth firmware, and ZLP quirk driver
 
 License:        GPL-2.0-only
 URL:            https://github.com/shenmintao/aic8800d80
@@ -22,9 +22,11 @@ Requires(post): /usr/sbin/depmod
 Requires(postun): /usr/sbin/depmod
 
 %description
-Out-of-tree AIC8800D80 USB Wi-Fi driver with udev mode-switch rules and all
-firmware variants shipped by the upstream repository. This main-branch package
-does not install a custom Bluetooth transport driver.
+Out-of-tree AIC8800 USB driver with Wi-Fi support, Bluetooth firmware loading,
+udev mode-switch rules, and all firmware variants shipped by the upstream
+repository. Combo adapters use the standard Linux btusb transport driver. A
+device-scoped companion module supplies the required ACL bulk TX ZLP behavior
+for USB device 368b:8d81 without replacing the distribution btusb module.
 
 %prep
 %autosetup -n %{name}-%{commit}
@@ -44,6 +46,10 @@ install -Dpm0644 \
   drivers/aic8800/aic_load_fw/aic_load_fw.ko \
   %{buildroot}/usr/lib/modules/%{kver}/kernel/drivers/net/wireless/aic8800/aic_load_fw.ko
 
+install -Dpm0644 \
+  drivers/aic8800/aic_zlp_quirk/aic_zlp_quirk.ko \
+  %{buildroot}/usr/lib/modules/%{kver}/kernel/drivers/bluetooth/aic8800/aic_zlp_quirk.ko
+
 install -Dpm0644 \
   aic.rules \
   %{buildroot}/usr/lib/udev/rules.d/90-aic8800-mode-switch.rules
@@ -65,11 +71,25 @@ cp -a fw/aic8800* %{buildroot}/usr/lib/firmware/
 %dir /usr/lib/modules/%{kver}/kernel/drivers/net/wireless/aic8800
 /usr/lib/modules/%{kver}/kernel/drivers/net/wireless/aic8800/aic8800_fdrv.ko
 /usr/lib/modules/%{kver}/kernel/drivers/net/wireless/aic8800/aic_load_fw.ko
+/usr/lib/modules/%{kver}/kernel/drivers/bluetooth/aic8800/aic_zlp_quirk.ko
 /usr/lib/udev/rules.d/90-aic8800-mode-switch.rules
 %config(noreplace) /etc/usb_modeswitch.d/1111:1111
 /usr/lib/firmware/aic8800*
 
 %changelog
+* Sat Jul 25 2026 Shen Mintao <shenmintao@gmail.com> - 51b7b6e-1
+- Package the unified installer and ZLP quirk with the legacy MCU1 profiles.
+- Preserve the matched D80 and DC/DW firmware and loader combinations.
+
+* Sat Jul 25 2026 Shen Mintao <shenmintao@gmail.com> - 13baa9b-1
+- Unify Wi-Fi and standard-btusb Bluetooth support in one package.
+- Add the device-scoped 368b:8d81 ACL bulk TX ZLP companion module.
+- Clean up obsolete aic_btusb and issue #63 diagnostic installations.
+
+* Fri Jul 24 2026 Shen Mintao <shenmintao@gmail.com> - 88dbc0a-1
+- Use the unified Wi-Fi and Bluetooth installer/package description.
+- Keep Bluetooth transport on the standard Linux btusb driver.
+
 * Tue Jul 14 2026 Shen Mintao <shenmintao@gmail.com> - d10bc52-1
 - Build the current main branch without the legacy custom Bluetooth module.
 - Package all firmware variants and current mode-switch rules.
diff --git a/diagnose_bt.sh b/diagnose_bt.sh
new file mode 100644
index 0000000..2448481
--- /dev/null
+++ b/diagnose_bt.sh
@@ -0,0 +1,160 @@
+#!/bin/bash
+# Diagnose Bluetooth on AIC8800 Wi-Fi/Bluetooth combo adapters.
+#
+# aic_load_fw initializes the device and uploads the AIC firmware. The
+# standard in-kernel btusb driver must then bind to the Bluetooth HCI USB
+# interface. The removed aic_btusb module must not be installed or loaded.
+
+echo "=== AIC8800 Bluetooth diagnostics ==="
+echo ""
+
+echo "1. AIC USB devices:"
+if command -v lsusb >/dev/null 2>&1; then
+    lsusb | grep -iE 'a69c|368b|3625' || echo "   No known AIC USB ID found"
+else
+    echo "   lsusb is not installed"
+fi
+echo ""
+
+echo "2. USB interfaces and bound drivers:"
+bt_interface_found=false
+btusb_bound=false
+zlp_target_found=false
+for dev in /sys/bus/usb/devices/*; do
+    [ -f "$dev/idVendor" ] || continue
+    [ -f "$dev/idProduct" ] || continue
+
+    vid=$(cat "$dev/idVendor" 2>/dev/null)
+    pid=$(cat "$dev/idProduct" 2>/dev/null)
+    case "$vid" in
+        a69c|368b|3625) ;;
+        *) continue ;;
+    esac
+
+    echo "   Device: $vid:$pid"
+    if [ "$vid" = "368b" ] && [ "$pid" = "8d81" ]; then
+        zlp_target_found=true
+    fi
+    for intf in "$dev"/*:*; do
+        [ -d "$intf" ] || continue
+        class=$(cat "$intf/bInterfaceClass" 2>/dev/null)
+        subclass=$(cat "$intf/bInterfaceSubClass" 2>/dev/null)
+        protocol=$(cat "$intf/bInterfaceProtocol" 2>/dev/null)
+        driver=$(basename "$(readlink "$intf/driver" 2>/dev/null)" 2>/dev/null)
+        echo "     $(basename "$intf"): ${class:-??}/${subclass:-??}/${protocol:-??} -> ${driver:-unbound}"
+
+        if [ "$driver" = "btusb" ]; then
+            btusb_bound=true
+            bt_interface_found=true
+        elif [ "$class" = "e0" ] && [ "$subclass" = "01" ] && [ "$protocol" = "01" ]; then
+            bt_interface_found=true
+        fi
+    done
+done
+echo ""
+
+echo "3. Relevant kernel modules (combo expectation: aic_load_fw + btusb):"
+lsmod | grep -E '^(aic_load_fw|aic8800_fdrv|aic_zlp_quirk|aic_btusb|btusb|bluetooth)[[:space:]]' || \
+    echo "   No related module is currently loaded"
+echo ""
+
+echo "4. Bluetooth controllers:"
+if command -v bluetoothctl >/dev/null 2>&1; then
+    bluetoothctl list 2>/dev/null || echo "   No controller reported by bluetoothctl"
+elif command -v hciconfig >/dev/null 2>&1; then
+    hciconfig -a 2>/dev/null || echo "   No controller reported by hciconfig"
+else
+    echo "   BlueZ command-line tools are not installed"
+fi
+echo ""
+
+echo "5. Firmware, btusb, ZLP quirk, and HCI log messages:"
+dmesg 2>/dev/null | grep -iE 'fw_patch|fw_adid|aicbt|aic_zlp_quirk|bluetooth|btusb|hci' | tail -80 || true
+echo ""
+
+echo "6. Bluetooth rfkill state:"
+if command -v rfkill >/dev/null 2>&1; then
+    rfkill list bluetooth 2>/dev/null || echo "   No Bluetooth rfkill entry"
+else
+    echo "   rfkill is not installed"
+fi
+echo ""
+
+echo "7. Obsolete aic_btusb installation/configuration:"
+legacy_refs_found=false
+mapfile -t legacy_modprobe_files < <(
+    grep -RIlE '^[[:space:]]*(softdep|alias)[^#]*aic_btusb([[:space:]]|$)' \
+        /etc/modprobe.d /run/modprobe.d /usr/local/lib/modprobe.d \
+        /usr/lib/modprobe.d /lib/modprobe.d 2>/dev/null | \
+        grep -vE '\.aic8800-backup$' || true
+)
+mapfile -t legacy_udev_files < <(
+    grep -RIl 'aic_btusb/new_id' \
+        /etc/udev/rules.d /run/udev/rules.d \
+        /usr/lib/udev/rules.d /lib/udev/rules.d 2>/dev/null | \
+        grep -vE '\.aic8800-backup$' || true
+)
+
+for legacy_file in "${legacy_modprobe_files[@]}"; do
+    echo "   Obsolete modprobe directive: $legacy_file"
+    legacy_refs_found=true
+done
+for legacy_file in "${legacy_udev_files[@]}"; do
+    echo "   Obsolete udev binding rule: $legacy_file"
+    legacy_refs_found=true
+done
+if lsmod | awk '{print $1}' | grep -qx 'aic_btusb'; then
+    echo "   Obsolete aic_btusb module is loaded"
+    legacy_refs_found=true
+fi
+if modinfo -n aic_btusb >/dev/null 2>&1; then
+    echo "   Obsolete module file: $(modinfo -n aic_btusb 2>/dev/null)"
+    legacy_refs_found=true
+fi
+if [ "$legacy_refs_found" = false ]; then
+    echo "   No active aic_btusb module, directive, or binding rule found (expected)"
+fi
+echo ""
+
+echo "8. Device-scoped Bluetooth ACL ZLP quirk:"
+if [ "$zlp_target_found" = true ]; then
+    if [ -d /sys/module/aic_zlp_quirk ]; then
+        zlp_hook="unknown"
+        zlp_injections="unavailable"
+        [ -r /sys/module/aic_zlp_quirk/parameters/hook ] && \
+            zlp_hook=$(cat /sys/module/aic_zlp_quirk/parameters/hook)
+        [ -r /sys/module/aic_zlp_quirk/parameters/injections ] && \
+            zlp_injections=$(cat /sys/module/aic_zlp_quirk/parameters/injections)
+        echo "   Target 368b:8d81 present"
+        echo "   aic_zlp_quirk loaded: yes"
+        echo "   active hook: $zlp_hook"
+        echo "   ZLP injections: $zlp_injections"
+    else
+        echo "   Target 368b:8d81 present, but aic_zlp_quirk is not loaded"
+    fi
+else
+    echo "   Target 368b:8d81 not present; quirk is not required"
+fi
+echo ""
+
+echo "=== Assessment ==="
+if ! lsmod | awk '{print $1}' | grep -qx 'aic_load_fw'; then
+    echo "- aic_load_fw is not loaded; run: sudo modprobe aic8800_fdrv"
+fi
+if [ "$bt_interface_found" = true ] && [ "$btusb_bound" = false ]; then
+    echo "- A Bluetooth USB interface exists but is not bound to btusb."
+    echo "  Check for a btusb blacklist, then try: sudo modprobe btusb"
+fi
+if dmesg 2>/dev/null | grep -iE 'hci[0-9]+:.*(command|opcode|tx).*timed out|hci[0-9]+: link tx timeout' | tail -1 | grep -q .; then
+    echo "- HCI timeout detected. Confirm that aic_load_fw uploaded the firmware before btusb bound."
+    echo "  Also check for obsolete aic_btusb configuration above."
+fi
+if [ "$bt_interface_found" = false ]; then
+    echo "- No Bluetooth HCI USB interface was found. This is normal for a Wi-Fi-only adapter."
+fi
+if [ "$zlp_target_found" = true ] && [ ! -d /sys/module/aic_zlp_quirk ]; then
+    echo "- Device 368b:8d81 requires the ACL ZLP quirk, but the module is not loaded."
+    echo "  Try: sudo modprobe aic_zlp_quirk"
+fi
+
+echo "=== Diagnostics complete ==="
diff --git a/dkms.conf b/dkms.conf
index ca060ed..4332d39 100644
--- a/dkms.conf
+++ b/dkms.conf
@@ -13,4 +13,9 @@ BUILT_MODULE_NAME[1]="aic_load_fw"
 BUILT_MODULE_LOCATION[1]="drivers/aic8800/aic_load_fw"
 DEST_MODULE_LOCATION[1]="/updates/dkms"
 
+# Device-scoped standard-btusb ACL bulk TX ZLP quirk (368b:8d81 only)
+BUILT_MODULE_NAME[2]="aic_zlp_quirk"
+BUILT_MODULE_LOCATION[2]="drivers/aic8800/aic_zlp_quirk"
+DEST_MODULE_LOCATION[2]="/updates/dkms"
+
 AUTOINSTALL="yes"
diff --git a/drivers/aic8800/Makefile b/drivers/aic8800/Makefile
index 54e658f..ee68eee 100644
--- a/drivers/aic8800/Makefile
+++ b/drivers/aic8800/Makefile
@@ -1,8 +1,10 @@
 CONFIG_AIC_LOADFW_SUPPORT := m
 CONFIG_AIC8800_WLAN_SUPPORT := m
+CONFIG_AIC_ZLP_QUIRK := m
 
 obj-$(CONFIG_AIC_LOADFW_SUPPORT)    += aic_load_fw/
 obj-$(CONFIG_AIC8800_WLAN_SUPPORT) += aic8800_fdrv/
+obj-$(CONFIG_AIC_ZLP_QUIRK)        += aic_zlp_quirk/
 
 ########## config option ##########
 export CONFIG_USE_FW_REQUEST = n
@@ -51,6 +53,7 @@ KVER ?= $(shell uname -r)
 KDIR ?= /lib/modules/$(KVER)/build
 PWD   = $(shell pwd)
 MODDESTDIR = /lib/modules/$(KVER)/kernel/drivers/net/wireless/aic8800
+BTMODDESTDIR = /lib/modules/$(KVER)/kernel/drivers/bluetooth/aic8800
 SUBARCH = $(shell uname -m | sed -e s/i.86/i386/ -e s/armv.l/arm/ -e s/aarch64/arm64/ -e s/loongarch64/loongarch/ -e s/loong64/loongarch/ -e s/riscv64/riscv/)
 ARCH ?= $(SUBARCH)
 CROSS_COMPILE ?=
@@ -78,16 +81,20 @@ modules:
 
 install:
 	mkdir -p $(MODDESTDIR)
+	mkdir -p $(BTMODDESTDIR)
 	install -p -m 644 aic_load_fw/aic_load_fw.ko  $(MODDESTDIR)/
 	install -p -m 644 aic8800_fdrv/aic8800_fdrv.ko  $(MODDESTDIR)/
+	install -p -m 644 aic_zlp_quirk/aic_zlp_quirk.ko  $(BTMODDESTDIR)/
 	/sbin/depmod -a ${KVER}
 
 uninstall:
 	rm -rfv $(MODDESTDIR)/aic_load_fw.ko
 	rm -rfv $(MODDESTDIR)/aic8800_fdrv.ko
+	rm -rfv $(BTMODDESTDIR)/aic_zlp_quirk.ko
 	/sbin/depmod -a ${KVER}
 
 clean:
 	cd aic_load_fw/;make clean;cd ..
 	cd aic8800_fdrv/;make clean;cd ..
+	cd aic_zlp_quirk/;make clean;cd ..
 	rm -rf modules.order Module.symvers .modules.order.cmd .Module.symvers.cmd .tmp_versions/
diff --git a/drivers/aic8800/aic_zlp_quirk/Makefile b/drivers/aic8800/aic_zlp_quirk/Makefile
new file mode 100644
index 0000000..8595f58
--- /dev/null
+++ b/drivers/aic8800/aic_zlp_quirk/Makefile
@@ -0,0 +1,18 @@
+ifneq ($(KERNELRELEASE),)
+
+obj-m += aic_zlp_quirk.o
+
+else
+
+KVER ?= $(shell uname -r)
+KDIR ?= /lib/modules/$(KVER)/build
+
+.PHONY: all clean
+
+all:
+	$(MAKE) -C $(KDIR) M=$(CURDIR) modules
+
+clean:
+	$(MAKE) -C $(KDIR) M=$(CURDIR) clean
+
+endif
diff --git a/drivers/aic8800/aic_zlp_quirk/aic_zlp_quirk.c b/drivers/aic8800/aic_zlp_quirk/aic_zlp_quirk.c
new file mode 100644
index 0000000..122bb68
--- /dev/null
+++ b/drivers/aic8800/aic_zlp_quirk/aic_zlp_quirk.c
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/atomic.h>
+#include <linux/kernel.h>
+#include <linux/kprobes.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/usb.h>
+
+#define AIC_USB_VENDOR_ID	0x368b
+#define AIC_USB_PRODUCT_ID	0x8d81
+#define USB_BT_SUBCLASS		0x01
+#define USB_BT_PROTOCOL		0x01
+
+static atomic64_t injection_count = ATOMIC64_INIT(0);
+static const char *hook_name = "none";
+
+static int injections_get(char *buffer, const struct kernel_param *kp)
+{
+	(void)kp;
+
+	return scnprintf(buffer, PAGE_SIZE, "%lld\n",
+			 (long long)atomic64_read(&injection_count));
+}
+
+static const struct kernel_param_ops injections_ops = {
+	.get = injections_get,
+};
+
+module_param_cb(injections, &injections_ops, NULL, 0444);
+MODULE_PARM_DESC(injections, "Number of AIC ACL bulk OUT URBs modified");
+
+static int hook_get(char *buffer, const struct kernel_param *kp)
+{
+	(void)kp;
+
+	return scnprintf(buffer, PAGE_SIZE, "%s\n", hook_name);
+}
+
+static const struct kernel_param_ops hook_ops = {
+	.get = hook_get,
+};
+
+module_param_cb(hook, &hook_ops, NULL, 0444);
+MODULE_PARM_DESC(hook, "Active injection hook");
+
+#if IS_ENABLED(CONFIG_KPROBES)
+
+enum aic_zlp_hook {
+	AIC_ZLP_HOOK_NONE,
+	AIC_ZLP_HOOK_BTUSB_RETURN,
+	AIC_ZLP_HOOK_USB_SUBMIT,
+};
+
+static enum aic_zlp_hook active_hook;
+
+static bool is_aic_bulk_out(const struct urb *urb)
+{
+	const struct usb_device *udev;
+
+	if (!urb)
+		return false;
+
+	udev = urb->dev;
+	if (!udev)
+		return false;
+
+	if (le16_to_cpu(udev->descriptor.idVendor) != AIC_USB_VENDOR_ID ||
+	    le16_to_cpu(udev->descriptor.idProduct) != AIC_USB_PRODUCT_ID)
+		return false;
+
+	return usb_pipetype(urb->pipe) == PIPE_BULK &&
+	       usb_pipeout(urb->pipe);
+}
+
+static bool is_bluetooth_acl_endpoint(const struct urb *urb)
+{
+	const struct usb_endpoint_descriptor *ep;
+	struct usb_host_interface *alt;
+	struct usb_interface *intf;
+	unsigned int endpoint;
+	int i;
+
+	if (!is_aic_bulk_out(urb))
+		return false;
+
+	intf = usb_ifnum_to_if(urb->dev, 0);
+	if (!intf)
+		return false;
+
+	alt = READ_ONCE(intf->cur_altsetting);
+	if (!alt ||
+	    alt->desc.bInterfaceClass != USB_CLASS_WIRELESS_CONTROLLER ||
+	    alt->desc.bInterfaceSubClass != USB_BT_SUBCLASS ||
+	    alt->desc.bInterfaceProtocol != USB_BT_PROTOCOL)
+		return false;
+
+	endpoint = usb_pipeendpoint(urb->pipe);
+	for (i = 0; i < alt->desc.bNumEndpoints; i++) {
+		ep = &alt->endpoint[i].desc;
+		if (usb_endpoint_is_bulk_out(ep) &&
+		    usb_endpoint_num(ep) == endpoint)
+			return true;
+	}
+
+	return false;
+}
+
+static void enable_zlp(struct urb *urb)
+{
+	long long count;
+
+	if (urb->transfer_flags & URB_ZERO_PACKET)
+		return;
+
+	urb->transfer_flags |= URB_ZERO_PACKET;
+	count = atomic64_inc_return(&injection_count);
+
+	if (count == 1)
+		pr_info("enabled ZLP on the first 368b:8d81 ACL bulk OUT URB\n");
+}
+
+static int alloc_bulk_urb_ret_handler(struct kretprobe_instance *ri,
+				      struct pt_regs *regs)
+{
+	struct urb *urb;
+
+	(void)ri;
+
+	urb = (struct urb *)regs_return_value(regs);
+	if (!is_aic_bulk_out(urb))
+		return 0;
+
+	enable_zlp(urb);
+	return 0;
+}
+
+static struct kretprobe alloc_bulk_urb_probe = {
+	.kp.symbol_name = "btusb:alloc_bulk_urb",
+	.handler = alloc_bulk_urb_ret_handler,
+};
+
+static int usb_submit_urb_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	struct urb *urb;
+
+	(void)p;
+
+	urb = (struct urb *)regs_get_kernel_argument(regs, 0);
+	if (is_bluetooth_acl_endpoint(urb))
+		enable_zlp(urb);
+
+	return 0;
+}
+
+static struct kprobe usb_submit_urb_probe = {
+	.symbol_name = "usb_submit_urb",
+	.pre_handler = usb_submit_urb_pre_handler,
+};
+
+static int __init aic_zlp_quirk_init(void)
+{
+	int ret;
+
+	ret = register_kretprobe(&alloc_bulk_urb_probe);
+	if (!ret) {
+		active_hook = AIC_ZLP_HOOK_BTUSB_RETURN;
+		hook_name = "btusb:alloc_bulk_urb";
+		pr_info("attached to system btusb for USB device 368b:8d81\n");
+		return 0;
+	}
+
+	pr_warn("btusb return hook unavailable (%d), trying USB submit fallback\n",
+		ret);
+
+	ret = register_kprobe(&usb_submit_urb_probe);
+	if (ret) {
+		pr_err("cannot attach to usb_submit_urb: %d\n", ret);
+		return ret;
+	}
+
+	active_hook = AIC_ZLP_HOOK_USB_SUBMIT;
+	hook_name = "usb_submit_urb";
+	pr_info("attached USB submit fallback for device 368b:8d81 interface 0\n");
+	return 0;
+}
+
+static void __exit aic_zlp_quirk_exit(void)
+{
+	unsigned long missed = 0;
+
+	if (active_hook == AIC_ZLP_HOOK_BTUSB_RETURN) {
+		unregister_kretprobe(&alloc_bulk_urb_probe);
+		missed = alloc_bulk_urb_probe.nmissed;
+	} else if (active_hook == AIC_ZLP_HOOK_USB_SUBMIT) {
+		unregister_kprobe(&usb_submit_urb_probe);
+		missed = usb_submit_urb_probe.nmissed;
+	}
+
+	pr_info("detached %s after %lld injections (%lu missed hits)\n",
+		hook_name, (long long)atomic64_read(&injection_count), missed);
+}
+
+#else
+
+static int __init aic_zlp_quirk_init(void)
+{
+	pr_err("CONFIG_KPROBES is disabled in this kernel\n");
+	return -EOPNOTSUPP;
+}
+
+static void __exit aic_zlp_quirk_exit(void)
+{
+}
+
+#endif
+
+module_init(aic_zlp_quirk_init);
+module_exit(aic_zlp_quirk_exit);
+
+MODULE_AUTHOR("Shen Mintao <cx330.shen@autocore.ai>");
+MODULE_DESCRIPTION("AIC 8800D80 standard btusb ACL bulk TX ZLP quirk");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.0");
+MODULE_SOFTDEP("pre: btusb");
+MODULE_ALIAS("usb:v368Bp8D81d*dc*dsc*dp*ic*isc*ip*in*");
diff --git a/install.sh b/install.sh
index 4d82ae3..4ddad4c 100755
--- a/install.sh
+++ b/install.sh
@@ -323,6 +323,62 @@ check_kernel_build_tree() {
 # Firmware Installation
 #############################################################################
 
+cleanup_legacy_bluetooth_config() {
+    local legacy_conf="/etc/modprobe.d/aic8800-bt.conf"
+    local legacy_udev="/etc/udev/rules.d/90-aic8800-mode-switch.rules"
+    local legacy_package
+    local changed=false
+
+    if [ -f "$legacy_conf" ] && grep -Eq '^[[:space:]]*(softdep|alias)[^#]*aic_btusb([[:space:]]|$)' "$legacy_conf"; then
+        print_info "Removing obsolete aic_btusb directives from $legacy_conf..."
+        if [ ! -f "${legacy_conf}.aic8800-backup" ]; then
+            cp -a "$legacy_conf" "${legacy_conf}.aic8800-backup" >> "$LOG_FILE" 2>&1
+        fi
+        sed -i -E '/^[[:space:]]*(softdep|alias)[^#]*aic_btusb([[:space:]]|$)/d' "$legacy_conf"
+        if ! grep -Eq '^[[:space:]]*[^#[:space:]]' "$legacy_conf"; then
+            rm -f "$legacy_conf"
+        fi
+        changed=true
+    fi
+
+    if [ -f "$legacy_udev" ] && grep -q 'aic_btusb/new_id' "$legacy_udev"; then
+        print_info "Removing obsolete aic_btusb binding rules from $legacy_udev..."
+        if [ ! -f "${legacy_udev}.aic8800-backup" ]; then
+            cp -a "$legacy_udev" "${legacy_udev}.aic8800-backup" >> "$LOG_FILE" 2>&1
+        fi
+        sed -i '/aic_btusb\/new_id/d' "$legacy_udev"
+        changed=true
+    fi
+
+    if lsmod | awk '{print $1}' | grep -qx 'aic_btusb'; then
+        print_info "Unloading obsolete aic_btusb module..."
+        if modprobe -r aic_btusb >> "$LOG_FILE" 2>&1; then
+            changed=true
+        else
+            print_warning "aic_btusb is still in use; reboot or replug the adapter after installation."
+        fi
+    fi
+
+    # Remove the two issue #63 diagnostic DKMS packages before the production
+    # quirk is installed as part of aic8800/1.0.0. A patched btusb may remain
+    # active in memory until reboot, but DKMS restores the distribution module
+    # on disk when its test package is removed.
+    for legacy_package in "btusb-aic-zlp/0.1" "aic-zlp-quirk/0.1"; do
+        if dkms status 2>/dev/null | grep -q "^${legacy_package},"; then
+            print_info "Removing superseded test package ${legacy_package}..."
+            if dkms remove "$legacy_package" --all >> "$LOG_FILE" 2>&1; then
+                changed=true
+            else
+                print_warning "Could not remove ${legacy_package}; remove it manually before reboot."
+            fi
+        fi
+    done
+
+    if [ "$changed" = true ]; then
+        print_success "Legacy Bluetooth configuration cleaned up."
+    fi
+}
+
 install_firmware() {
     print_step "Installing firmware..."
 
@@ -334,6 +390,8 @@ install_firmware() {
         exit 1
     fi
 
+    cleanup_legacy_bluetooth_config
+
     # Remove old firmware versions
     if [ -d "/lib/firmware" ] && [ -n "$(find /lib/firmware -maxdepth 1 -name 'aic8800*' -type d 2>/dev/null)" ]; then
         print_info "Removing existing firmware..."
@@ -351,6 +409,8 @@ install_firmware() {
         fi
     done
 
+    print_success "Firmware installed for all supported chip variants."
+
     # Install udev rules
     local rules_source="${SCRIPT_DIR}/aic.rules"
     local rules_dest="/usr/lib/udev/rules.d/aic.rules"
@@ -416,6 +476,11 @@ BUILT_MODULE_NAME[1]="aic_load_fw"
 BUILT_MODULE_LOCATION[1]="drivers/aic8800/aic_load_fw"
 DEST_MODULE_LOCATION[1]="/updates/dkms"
 
+# Quirk ZLP para Bluetooth ACL bulk TX (somente 368b:8d81)
+BUILT_MODULE_NAME[2]="aic_zlp_quirk"
+BUILT_MODULE_LOCATION[2]="drivers/aic8800/aic_zlp_quirk"
+DEST_MODULE_LOCATION[2]="/updates/dkms"
+
 AUTOINSTALL="yes"
 EOF
     
@@ -525,23 +590,38 @@ refresh_initramfs() {
 # Module Loading
 #############################################################################
 
+aic_zlp_target_present() {
+    local device
+
+    for device in /sys/bus/usb/devices/*; do
+        [ -r "$device/idVendor" ] || continue
+        [ -r "$device/idProduct" ] || continue
+        [ "$(cat "$device/idVendor")" = "368b" ] || continue
+        [ "$(cat "$device/idProduct")" = "8d81" ] || continue
+        return 0
+    done
+
+    return 1
+}
+
 load_module() {
-    print_step "Loading kernel module..."
+    print_step "Loading kernel modules..."
     
     # Update module dependencies
     print_info "Updating module dependencies..."
     depmod -a >> "$LOG_FILE" 2>&1
     
-    # Unload module if already loaded
     if lsmod | grep -q "$MODULE_NAME"; then
-        print_info "Module already loaded. Reloading..."
+        print_info "Wi-Fi module already loaded. Reloading..."
         modprobe -r "$MODULE_NAME" >> "$LOG_FILE" 2>&1 || true
     fi
     
-    # Load the module
+    # aic8800_fdrv depends on aic_load_fw, which initializes both Wi-Fi-only
+    # adapters and the Bluetooth firmware on combo adapters. If a standard HCI
+    # USB interface appears afterwards, the kernel USB modalias loads btusb.
     print_info "Loading $MODULE_NAME..."
     if modprobe "$MODULE_NAME" >> "$LOG_FILE" 2>&1; then
-        print_success "Module loaded successfully."
+        print_success "Wi-Fi module loaded successfully."
         
         # Verify module is loaded
         print_info "Waiting for module to initialize..."
@@ -555,15 +635,30 @@ load_module() {
         done
         
         if [ "$module_loaded" = true ]; then
-            print_success "Module is active in kernel."
+            print_success "Wi-Fi module is active in kernel."
         else
-            print_warning "Module may not be fully initialized yet."
+            print_warning "Wi-Fi module may not be fully initialized yet."
         fi
     else
-        print_warning "Module installed but could not be loaded immediately."
+        print_warning "Wi-Fi module installed but could not be loaded immediately."
         print_info "This may be due to Secure Boot or missing hardware."
         print_info "Try rebooting or check: sudo dmesg | grep aic8800"
     fi
+
+    print_info "Combo adapters use the standard btusb driver when their Bluetooth interface appears."
+
+    # The module has a USB alias and normally autoloads when 368b:8d81 appears.
+    # Explicitly load it here as well when that device was already present before
+    # DKMS installation and therefore did not generate a new modalias event.
+    if aic_zlp_target_present; then
+        print_info "Loading the 368b:8d81 Bluetooth ACL ZLP quirk..."
+        if modprobe aic_zlp_quirk >> "$LOG_FILE" 2>&1; then
+            print_success "Device-scoped Bluetooth ZLP quirk is active."
+        else
+            print_warning "The ZLP quirk could not attach; system btusb remains unchanged."
+            print_info "Check CONFIG_KPROBES, Secure Boot, and: sudo dmesg | grep aic_zlp_quirk"
+        fi
+    fi
 }
 
 #############################################################################
@@ -583,14 +678,36 @@ verify_installation() {
         print_warning "DKMS status unclear: $dkms_status"
     fi
     
-    # Check if module is loaded
+    # Check if the Wi-Fi module is loaded
     if lsmod | grep -q "$MODULE_NAME"; then
-        print_success "Kernel module is loaded."
-        echo ""
-        lsmod | grep aic
+        print_success "Wi-Fi kernel module is loaded."
     else
-        print_info "Module not currently loaded (this is OK if no hardware is connected)."
+        print_info "Wi-Fi module not currently loaded (this is OK if no hardware is connected)."
     fi
+
+    if lsmod | awk '{print $1}' | grep -qx 'btusb' || compgen -G '/sys/class/bluetooth/hci*' > /dev/null; then
+        print_success "A Bluetooth controller or the standard btusb module is present."
+    else
+        print_info "No Bluetooth controller is present (normal for Wi-Fi-only adapters or when no combo adapter is connected)."
+    fi
+
+    if aic_zlp_target_present; then
+        if lsmod | awk '{print $1}' | grep -qx 'aic_zlp_quirk'; then
+            local zlp_hook="unknown"
+            if [ -r /sys/module/aic_zlp_quirk/parameters/hook ]; then
+                zlp_hook=$(cat /sys/module/aic_zlp_quirk/parameters/hook)
+            fi
+            print_success "Bluetooth ACL ZLP quirk is loaded (hook: $zlp_hook)."
+        else
+            print_warning "USB device 368b:8d81 is present but aic_zlp_quirk is not loaded."
+        fi
+    else
+        print_info "Bluetooth ZLP quirk is installed but inactive (no 368b:8d81 device present)."
+    fi
+
+    echo ""
+    print_info "Loaded AIC modules:"
+    lsmod | grep aic || echo "  (none)"
     
     # Check firmware
     local fw_count=0
@@ -610,6 +727,15 @@ verify_installation() {
     if command -v iwconfig &> /dev/null; then
         iwconfig 2>/dev/null | grep -E "wlan|IEEE" || echo "No wireless interfaces detected (hardware may not be connected)"
     fi
+
+    print_info "Checking for Bluetooth interfaces on combo adapters..."
+    if command -v bluetoothctl &> /dev/null; then
+        bluetoothctl list 2>/dev/null || echo "No Bluetooth interfaces detected (normal for Wi-Fi-only adapters)"
+    elif command -v hciconfig &> /dev/null; then
+        hciconfig 2>/dev/null || echo "No Bluetooth interfaces detected (normal for Wi-Fi-only adapters)"
+    else
+        echo "Bluetooth tools not installed (install BlueZ to manage a combo adapter)"
+    fi
 }
 
 #############################################################################
@@ -624,13 +750,15 @@ show_final_instructions() {
     echo ""
     echo -e "${CYAN}Important Information:${NC}"
     echo ""
-    echo "✓ Driver installed via DKMS"
+    echo "✓ Wi-Fi driver and firmware loader installed via DKMS"
+    echo "✓ Combo adapters use the standard Linux btusb driver"
+    echo "✓ Device-scoped Bluetooth ACL ZLP quirk installed for 368b:8d81"
     echo "✓ Automatic rebuild enabled for kernel updates"
     echo "✓ Firmware installed in /lib/firmware/"
     echo ""
     echo -e "${CYAN}Next Steps:${NC}"
     echo ""
-    echo "1. Connect your AIC8800D80 USB WiFi adapter"
+    echo "1. Connect your AIC8800 USB Wi-Fi or Wi-Fi/Bluetooth adapter"
     echo ""
     echo "2. Check if the adapter is detected:"
     echo "   ${BLUE}lsusb | grep -i aic${NC}"
@@ -639,32 +767,37 @@ show_final_instructions() {
     echo ""
     echo "3. View kernel messages about the driver:"
     echo "   ${BLUE}sudo dmesg | grep aic8800${NC}"
+    echo "   ${BLUE}sudo dmesg | grep -iE 'bluetooth|btusb|hci'${NC}"
     echo ""
     echo "4. Connect to a WiFi network:"
     echo "   ${BLUE}nmcli device wifi list${NC}"
     echo "   ${BLUE}nmcli device wifi connect \"SSID\" password \"PASSWORD\"${NC}"
     echo ""
+    echo "5. For a combo adapter, check Bluetooth:"
+    echo "   ${BLUE}bluetoothctl list${NC}"
+    echo "   ${BLUE}bluetoothctl scan on${NC}"
+    echo ""
     echo -e "${CYAN}Troubleshooting:${NC}"
     echo ""
     echo "• Check DKMS status:"
     echo "  ${BLUE}dkms status${NC}"
     echo ""
     echo "• Check loaded modules:"
-    echo "  ${BLUE}lsmod | grep aic8800${NC}"
+    echo "  ${BLUE}lsmod | grep -E 'aic|btusb'${NC}"
+    echo "  ${BLUE}cat /sys/module/aic_zlp_quirk/parameters/{hook,injections}${NC}"
     echo ""
-    echo "• Manually load the module:"
+    echo "• Manually load the Wi-Fi module and firmware loader:"
     echo "  ${BLUE}sudo modprobe aic8800_fdrv${NC}"
     echo ""
     echo "• View detailed logs:"
     echo "  ${BLUE}cat $LOG_FILE${NC}"
     echo ""
     echo -e "${YELLOW}Known Limitations:${NC}"
-    echo "• Bluetooth functionality is not supported"
     echo "• Secure Boot may prevent module loading (disable in BIOS if needed)"
     echo ""
     echo -e "${CYAN}Uninstallation:${NC}"
     echo "  ${BLUE}sudo dkms remove ${DRV_NAME}/${DRV_VERSION} --all${NC}"
-    echo "  ${BLUE}sudo rm -rf /lib/firmware/aic8800D80${NC}"
+    echo "  ${BLUE}sudo rm -rf /lib/firmware/aic8800*${NC}"
     echo ""
 }
 
diff --git a/tests/issue63-zlp-quirk/Makefile b/tests/issue63-zlp-quirk/Makefile
new file mode 100644
index 0000000..26ad7b0
--- /dev/null
+++ b/tests/issue63-zlp-quirk/Makefile
@@ -0,0 +1,12 @@
+KVER ?= $(shell uname -r)
+KDIR ?= /lib/modules/$(KVER)/build
+
+obj-m += aic_zlp_quirk.o
+
+.PHONY: all clean
+
+all:
+	$(MAKE) -C $(KDIR) M=$(CURDIR) modules
+
+clean:
+	$(MAKE) -C $(KDIR) M=$(CURDIR) clean
diff --git a/tests/issue63-zlp-quirk/README.md b/tests/issue63-zlp-quirk/README.md
new file mode 100644
index 0000000..7d62b3c
--- /dev/null
+++ b/tests/issue63-zlp-quirk/README.md
@@ -0,0 +1,109 @@
+# Issue #63: standard `btusb` ACL ZLP support
+
+The `aic_zlp_quirk` companion module supplies the Bluetooth ACL bulk TX
+zero-length-packet behavior confirmed in
+[issue #63](https://github.com/shenmintao/aic8800d80/issues/63). It is now part
+of the normal `aic8800` DKMS build rather than a replacement for the
+distribution's Bluetooth driver.
+
+The validated failure was specific and reproducible: AAC playback through USB
+device `368b:8d81` stalled after about one minute, while SBC remained stable.
+Adding `URB_ZERO_PACKET` to the ACL bulk OUT URBs kept AAC connected for more
+than one hour. The standalone module was then verified with the system
+`btusb`, no loaded `aic_btusb`, and 2,113 observed ZLP injections.
+
+## Architecture and scope
+
+The module first tries to attach a kretprobe to the standard `btusb` function
+that allocates ACL bulk OUT URBs. The target is module-qualified as
+`btusb:alloc_bulk_urb`, avoiding similarly named symbols in unrelated USB
+drivers.
+
+Some distribution builds inline that private function. When the preferred hook
+is unavailable, the module falls back to the stable `usb_submit_urb` entry
+point. The fallback changes an URB only when all of these checks pass:
+
+- USB device is exactly `368b:8d81`;
+- the transfer is bulk OUT;
+- the endpoint belongs to Bluetooth interface 0 (`e0/01/01`).
+
+Both paths add only `URB_ZERO_PACKET`. Wi-Fi interfaces and unrelated USB
+devices are unchanged. If neither probe can be installed or kprobes are
+disabled, the module refuses to load and system `btusb` remains unchanged.
+
+The module carries a USB modalias for `368b:8d81`, so it is inactive on other
+hardware and normally autoloads only when the validated device appears.
+
+## Install from the unified branch
+
+```bash
+git fetch origin
+git switch test/unified-wifi-bt-zlp
+git pull --ff-only
+sudo ./install.sh
+sudo reboot
+```
+
+The installer removes the earlier `btusb-aic-zlp/0.1` and
+`aic-zlp-quirk/0.1` diagnostic DKMS packages when present. To remove them
+manually before installation, use:
+
+```bash
+sudo dkms remove btusb-aic-zlp/0.1 --all
+sudo dkms remove aic-zlp-quirk/0.1 --all
+sudo depmod -a
+```
+
+The unified installer also removes active configuration left by the obsolete
+custom `aic_btusb` transport.
+
+## Verify
+
+Confirm that system `btusb` owns Bluetooth interfaces 0/1 and that the quirk is
+loaded:
+
+```bash
+lsusb -t
+lsmod | grep -E '^(btusb|aic_zlp_quirk|aic_btusb)\b'
+modinfo -n btusb
+modinfo -n aic_zlp_quirk
+cat /sys/module/aic_zlp_quirk/parameters/hook
+cat /sys/module/aic_zlp_quirk/parameters/injections
+sudo ./diagnose_bt.sh
+```
+
+Expected results include:
+
+```text
+Bluetooth interfaces 0/1: btusb
+aic_btusb: not loaded
+aic_zlp_quirk: loaded
+active hook: btusb:alloc_bulk_urb
+```
+
+`active hook: usb_submit_urb` is also valid when the compiler inlined the
+preferred function. During Bluetooth traffic, the `injections` value must
+increase.
+
+For the promotion test, select AAC and play audio for at least one hour while
+also confirming that Wi-Fi scan, association, DHCP, and real traffic remain
+working.
+
+## Isolated retest helper
+
+`aic-zlp-quirk-test.sh` remains available only for isolated issue #63 retests.
+It builds the same canonical source from
+`drivers/aic8800/aic_zlp_quirk/aic_zlp_quirk.c` as a separate DKMS package. A
+normal installation should use the repository-level `install.sh` instead.
+
+## Kernel requirements
+
+- matching kernel headers;
+- `CONFIG_KPROBES=y` and kretprobe support;
+- standard `btusb` plus either its `alloc_bulk_urb` symbol or the USB core
+  `usb_submit_urb` symbol;
+- a valid module signature when Secure Boot policy requires one.
+
+The preferred function has the same signature in Linux 5.15, 6.1, 6.6, 6.12,
+6.18, and 7.1.3, although compilers may inline it. DKMS builds one module for
+each installed kernel from the single canonical source file.
diff --git a/tests/issue63-zlp-quirk/aic-zlp-quirk-test.sh b/tests/issue63-zlp-quirk/aic-zlp-quirk-test.sh
new file mode 100755
index 0000000..544062a
--- /dev/null
+++ b/tests/issue63-zlp-quirk/aic-zlp-quirk-test.sh
@@ -0,0 +1,239 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+PACKAGE_NAME="aic-zlp-quirk"
+PACKAGE_VERSION="0.1"
+MODULE_NAME="aic_zlp_quirk"
+KERNEL_RELEASE="${KERNEL_RELEASE:-$(uname -r)}"
+KERNEL_BUILD_DIR="/lib/modules/${KERNEL_RELEASE}/build"
+SOURCE_DIR="/usr/src/${PACKAGE_NAME}-${PACKAGE_VERSION}"
+MODULES_LOAD_FILE="/etc/modules-load.d/${PACKAGE_NAME}.conf"
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+REPO_ROOT="$(cd -- "${SCRIPT_DIR}/../.." && pwd)"
+QUIRK_SOURCE="${REPO_ROOT}/drivers/aic8800/aic_zlp_quirk/aic_zlp_quirk.c"
+
+log() {
+    printf '[aic-zlp-quirk-test] %s\n' "$*"
+}
+
+die() {
+    printf '[aic-zlp-quirk-test] ERROR: %s\n' "$*" >&2
+    exit 1
+}
+
+require_root() {
+    [ "$(id -u)" -eq 0 ] || die "run this command as root"
+}
+
+require_command() {
+    command -v "$1" >/dev/null 2>&1 || die "required command not found: $1"
+}
+
+stop_bluetooth() {
+    if command -v systemctl >/dev/null 2>&1; then
+        systemctl stop bluetooth.service 2>/dev/null || true
+    fi
+}
+
+start_bluetooth() {
+    if command -v systemctl >/dev/null 2>&1; then
+        systemctl start bluetooth.service 2>/dev/null || true
+    fi
+}
+
+module_loaded() {
+    [ -d "/sys/module/$1" ]
+}
+
+legacy_btusb_loaded() {
+    module_loaded aic_btusb
+}
+
+patched_btusb_installed() {
+    dkms status -m btusb-aic-zlp -v 0.1 2>/dev/null | grep -q .
+}
+
+copy_sources() {
+    install -d "${SOURCE_DIR}"
+    install -m 0644 "${QUIRK_SOURCE}" "${SOURCE_DIR}/"
+    install -m 0644 "${SCRIPT_DIR}/Makefile" "${SOURCE_DIR}/"
+    install -m 0644 "${SCRIPT_DIR}/dkms.conf" "${SOURCE_DIR}/"
+}
+
+rollback_install() {
+    log "rolling back the ZLP companion module"
+    rm -f -- "${MODULES_LOAD_FILE}"
+    modprobe -r "${MODULE_NAME}" >/dev/null 2>&1 || true
+    dkms remove -m "${PACKAGE_NAME}" -v "${PACKAGE_VERSION}" --all >/dev/null 2>&1 || true
+    rm -rf -- "${SOURCE_DIR}"
+    depmod -a "${KERNEL_RELEASE}" >/dev/null 2>&1 || true
+    start_bluetooth
+}
+
+verify_standard_btusb() {
+    if legacy_btusb_loaded; then
+        die "obsolete aic_btusb is loaded; run 'sudo modprobe -r aic_btusb' and remove its old autoload configuration first"
+    fi
+
+    if patched_btusb_installed; then
+        die "the patched btusb test package is still installed; remove it before testing the companion module"
+    fi
+
+    modprobe btusb || die "could not load the system btusb module"
+}
+
+install_module() {
+    require_root
+    require_command dkms
+    require_command make
+    require_command modprobe
+    require_command depmod
+
+    [ -r "${KERNEL_BUILD_DIR}/Makefile" ] || \
+        die "kernel build tree not found: ${KERNEL_BUILD_DIR}"
+
+    if command -v lsusb >/dev/null 2>&1 && ! lsusb -d 368b:8d81 >/dev/null 2>&1; then
+        die "this test is restricted to USB device 368b:8d81, which is not connected"
+    fi
+
+    verify_standard_btusb
+
+    if module_loaded "${MODULE_NAME}"; then
+        log "unloading the earlier companion module"
+        if ! modprobe -r "${MODULE_NAME}"; then
+            die "could not unload the earlier ${MODULE_NAME} module"
+        fi
+    fi
+
+    trap rollback_install ERR
+
+    if dkms status -m "${PACKAGE_NAME}" -v "${PACKAGE_VERSION}" 2>/dev/null | grep -q .; then
+        log "removing an earlier companion-module build"
+        dkms remove -m "${PACKAGE_NAME}" -v "${PACKAGE_VERSION}" --all
+    fi
+
+    rm -rf -- "${SOURCE_DIR}"
+    copy_sources
+
+    log "building the ZLP companion module for ${KERNEL_RELEASE}"
+    dkms add -m "${PACKAGE_NAME}" -v "${PACKAGE_VERSION}"
+    dkms build -m "${PACKAGE_NAME}" -v "${PACKAGE_VERSION}" -k "${KERNEL_RELEASE}"
+    dkms install -m "${PACKAGE_NAME}" -v "${PACKAGE_VERSION}" \
+        -k "${KERNEL_RELEASE}" --force
+    depmod -a "${KERNEL_RELEASE}"
+
+    printf '%s\n' "${MODULE_NAME}" > "${MODULES_LOAD_FILE}"
+
+    stop_bluetooth
+    if ! modprobe "${MODULE_NAME}"; then
+        trap - ERR
+        rollback_install
+        die "the companion module could not attach; the system btusb was left unchanged"
+    fi
+    start_bluetooth
+    trap - ERR
+
+    log "loaded module: $(modinfo -n "${MODULE_NAME}")"
+    log "system btusb remains active; test AAC playback for at least one hour"
+}
+
+remove_module() {
+    require_root
+    require_command dkms
+    require_command modprobe
+    require_command depmod
+
+    stop_bluetooth
+    rm -f -- "${MODULES_LOAD_FILE}"
+    if module_loaded "${MODULE_NAME}" && ! modprobe -r "${MODULE_NAME}"; then
+        start_bluetooth
+        die "could not unload ${MODULE_NAME}; no files were removed"
+    fi
+    if dkms status -m "${PACKAGE_NAME}" -v "${PACKAGE_VERSION}" 2>/dev/null | grep -q .; then
+        if ! dkms remove -m "${PACKAGE_NAME}" -v "${PACKAGE_VERSION}" --all; then
+            start_bluetooth
+            die "DKMS removal failed; source files were left in place"
+        fi
+    fi
+    rm -rf -- "${SOURCE_DIR}"
+    depmod -a "${KERNEL_RELEASE}"
+    start_bluetooth
+
+    log "removed the companion module; the distribution btusb was never replaced"
+}
+
+show_aic_binding() {
+    local device
+    local driver
+
+    for device in /sys/bus/usb/devices/*; do
+        [ -r "${device}/idVendor" ] || continue
+        [ -r "${device}/idProduct" ] || continue
+        [ "$(cat "${device}/idVendor")" = "368b" ] || continue
+        [ "$(cat "${device}/idProduct")" = "8d81" ] || continue
+
+        driver="not bound"
+        if [ -L "${device}:1.0/driver" ]; then
+            driver="$(basename "$(readlink -f "${device}:1.0/driver")")"
+        fi
+
+        printf 'AIC BT driver: %s\n' "${driver}"
+        return
+    done
+
+    printf 'AIC BT driver: device not found\n'
+}
+
+show_status() {
+    local loaded="no"
+    local injections="unavailable"
+    local hook="unavailable"
+    local integrated_dkms_status
+    local standalone_dkms_status
+
+    if module_loaded "${MODULE_NAME}"; then
+        loaded="yes"
+        if [ -r "/sys/module/${MODULE_NAME}/parameters/injections" ]; then
+            injections="$(cat "/sys/module/${MODULE_NAME}/parameters/injections")"
+        fi
+        if [ -r "/sys/module/${MODULE_NAME}/parameters/hook" ]; then
+            hook="$(cat "/sys/module/${MODULE_NAME}/parameters/hook")"
+        fi
+    fi
+
+    standalone_dkms_status="$(dkms status -m "${PACKAGE_NAME}" -v "${PACKAGE_VERSION}" 2>/dev/null || true)"
+    if [ -z "${standalone_dkms_status}" ]; then
+        standalone_dkms_status="not installed"
+    fi
+    integrated_dkms_status="$(dkms status -m aic8800 -v 1.0.0 2>/dev/null || true)"
+    if [ -z "${integrated_dkms_status}" ]; then
+        integrated_dkms_status="not installed"
+    fi
+
+    printf 'kernel:        %s\n' "${KERNEL_RELEASE}"
+    printf 'btusb module:  %s\n' "$(modinfo -n btusb 2>/dev/null || printf 'not found')"
+    printf 'quirk module:  %s\n' "$(modinfo -n "${MODULE_NAME}" 2>/dev/null || printf 'not found')"
+    printf 'quirk loaded:  %s\n' "${loaded}"
+    printf 'active hook:   %s\n' "${hook}"
+    printf 'ZLP injections:%s\n' " ${injections}"
+    printf 'legacy aic_btusb: %s\n' "$(legacy_btusb_loaded && printf 'loaded' || printf 'not loaded')"
+    printf 'integrated DKMS: %s\n' "${integrated_dkms_status}"
+    printf 'standalone DKMS: %s\n' "${standalone_dkms_status}"
+    show_aic_binding
+}
+
+case "${1:-}" in
+    install)
+        install_module
+        ;;
+    remove)
+        remove_module
+        ;;
+    status)
+        show_status
+        ;;
+    *)
+        printf 'Usage: %s {install|remove|status}\n' "$0" >&2
+        exit 2
+        ;;
+esac
diff --git a/tests/issue63-zlp-quirk/dkms.conf b/tests/issue63-zlp-quirk/dkms.conf
new file mode 100644
index 0000000..1795467
--- /dev/null
+++ b/tests/issue63-zlp-quirk/dkms.conf
@@ -0,0 +1,10 @@
+PACKAGE_NAME="aic-zlp-quirk"
+PACKAGE_VERSION="0.1"
+
+MAKE[0]="make KVER=${kernelver}"
+CLEAN="make KVER=${kernelver} clean"
+
+BUILT_MODULE_NAME[0]="aic_zlp_quirk"
+DEST_MODULE_LOCATION[0]="/updates/dkms"
+
+AUTOINSTALL="yes"
diff --git a/tests/unified-wifi-bt/README.md b/tests/unified-wifi-bt/README.md
new file mode 100644
index 0000000..dc74a5b
--- /dev/null
+++ b/tests/unified-wifi-bt/README.md
@@ -0,0 +1,87 @@
+# Unified Wi-Fi, Bluetooth, and ZLP branch test
+
+This branch tests replacing the separate `main` and `bluetooth` branches with
+one driver and installer. The Wi-Fi driver and firmware were already identical
+on both branches. This test unifies their installer, migration, diagnostics,
+packaging, and documentation, and adds the device-scoped ZLP fix from issue
+#63 as a third DKMS module.
+
+The expected architecture is:
+
+- `aic_load_fw` initializes every supported adapter and uploads firmware.
+- `aic8800_fdrv` handles Wi-Fi.
+- A combo adapter exposes a Bluetooth HCI USB interface after initialization;
+  the standard Linux `btusb` driver binds through normal USB device matching.
+- A Wi-Fi-only adapter exposes no HCI interface and does not need `btusb`.
+- The retired custom `aic_btusb` module is never installed or used.
+- USB device `368b:8d81` autoloads `aic_zlp_quirk`, which adds
+  `URB_ZERO_PACKET` only to its Bluetooth ACL bulk OUT transfers.
+- The distribution's original `btusb.ko` is never replaced.
+
+The installer deliberately does not force-load `btusb` and does not globally
+unblock Bluetooth through rfkill.
+
+## Install
+
+```bash
+git fetch origin
+git switch test/unified-wifi-bt-zlp
+git pull --ff-only
+sudo ./install.sh
+sudo reboot
+```
+
+## Test a Wi-Fi-only adapter
+
+Confirm that:
+
+1. The Wi-Fi interface is created.
+2. Scanning, association, DHCP, and real traffic work.
+3. No `aic_btusb` module is loaded.
+4. The absence of `btusb` or an HCI controller is treated as normal.
+
+## Test a Wi-Fi/Bluetooth combo adapter
+
+Confirm that:
+
+1. Wi-Fi scanning, association, DHCP, and real traffic work.
+2. `aic_load_fw` uploads the firmware before the HCI interface is used.
+3. The Bluetooth USB interface is bound to the standard `btusb` driver.
+4. `bluetoothctl` can power on, scan, pair, and exchange real traffic.
+5. No `aic_btusb` module, alias, soft dependency, or udev binding rule remains.
+
+## Test the `368b:8d81` ZLP path
+
+In addition to the combo-adapter checks, confirm that:
+
+1. `aic_zlp_quirk` loads automatically and system `btusb` owns interfaces 0/1.
+2. `hook` reports `btusb:alloc_bulk_urb` or `usb_submit_urb`.
+3. The `injections` counter increases during Bluetooth audio traffic.
+4. AAC playback remains connected for at least one hour.
+5. Wi-Fi scan, association, and traffic remain unaffected during the test.
+
+## Collect results
+
+```bash
+git rev-parse --short HEAD
+lsusb
+lsusb -t
+lsmod | grep -E 'aic|btusb|bluetooth'
+iw dev
+bluetoothctl list
+cat /sys/module/aic_zlp_quirk/parameters/{hook,injections} 2>/dev/null || true
+sudo ./diagnose_bt.sh | tee unified-wifi-bt-diagnostic.log
+sudo journalctl -k -b --no-pager | tee unified-wifi-bt-kernel.log
+```
+
+Please attach both logs and identify whether the tested adapter is Wi-Fi-only
+or a combo device.
+
+## Roll back during testing
+
+```bash
+git switch main
+git pull --ff-only
+sudo ./install.sh
+sudo reboot
+```