btusb-csr8510-fix-fix

Fix for the Patch for the btusb kernel module to restore support for fake CSR8510 A10 Bluetooth dongles (10d7:b012) broken by an upstream kernel change that only accounted for the original CSR vendor/product ID (0a12:0001).

Problem

The script was broken with tab syntax.

A kernel fix for fake CSR Bluetooth adapters hardcodes checks for 0a12:0001 in three places within drivers/bluetooth/btusb.c. Other fake CSR clones like 10d7:b012 are not handled, causing them to malfunction or stop working entirely after the update.

What the patch does

Fixes the tab syntax in the script.

Adds device ID 10d7:b012 to the three relevant code paths in btusb.c:

1. quirks_table — Registers the device with BTUSB_CSR driver info so it enters the CSR code path.
2. Interrupt transfer size — Uses wMaxPacketSize instead of HCI_MAX_EVENT_SIZE, matching the behavior required by fake CSR devices.
3. Setup function — Routes the device through btusb_setup_csr() to handle broken HCI commands.

Requirements

• Fedora / Nobara (or any distro with kernel-devel packages)
• kernel-devel for your running kernel
• gcc, make, curl, zstd

sudo dnf install kernel-devel gcc make curl zstd

Usage

git clone https://github.com/ewood/btusb-csr8510-fix.git
cd btusb-csr8510-fix
sudo ./patch.sh

The script will:

1. Download btusb.c and headers matching your running kernel
2. Apply the three patches
3. Compile the module
4. Back up the original module
5. Install the patched module
6. Reload btusb

Reverting

sudo cp /lib/modules/$(uname -r)/kernel/drivers/bluetooth/btusb.ko.zst.bak \
        /lib/modules/$(uname -r)/kernel/drivers/bluetooth/btusb.ko.zst
sudo rmmod btusb && sudo modprobe btusb

After kernel updates

The patch applies to the compiled module, not the kernel source. You need to re-run the script after every kernel update.

Verifying your device

Check if your adapter matches the affected device ID:

lsusb | grep -i 10d7

Expected output:

Bus XXX Device XXX: ID 10d7:b012 Majesty Internal ... CSR8510 A10

This was inspired by this comment: https://discussion.fedoraproject.org/t/bluetooth-not-working-on-fedora-41-csr8510-a10-linux-6-12-4-200-fc41-x86-64/139742/8

This patch modifies Linux kernel source code licensed under GPL-2.0.