Some wireless cards have the region set to 0x0 in firmware, and recent versions of the Linux kernel (since 5.8?) interpret this as the "global" region 0x64 which is very restrictive and does not allow setting an alternate region. This basically completely breaks functionality for 5Ghz bands. This affects the Compex Mini-PCI and Mini-PCIe cards often sold with pcengines ALIX and APU2 boards, which make great wireless access points/routers.
This repository contains DKMS directories for patched version of the drivers, which uses the default country code (typically US) rather than world regulatory domain when the bad 0x0 region is set.
The dkms.conf only rebuilds the ath module; all dependent modules, most
notably ath9k and ath10k, should work with the changes without being rebuilt.
As root (or with sudo):
apt install dkms linux-headers
cp -R athregd-5.10.0-8 /usr/src
dkms install --no-depmod -m athregd -v 5.10.0-8 -k $(uname -r)
Stop any connections or hostapd daemons running on the interface, then remove the modules, check that the new module built with dkms is installed, and re-load the driver module. For example, for ath9k (as root):
modprobe -r ath9k ath9k_hw ath ath9k_common
depmod -a
modinfo ath | grep filename # should show new dkms location
modprobe ath9k
Note: the default kernel for 20.40, 5.4, does not have this bug. However if you need / want a newer kernel, you can use this method to retain functionality with the HWE kernel.
As root (or with sudo):
apt install dkms linux-image-generic-hwe-20.04 linux-headers-generic-hwe-20.04
cp -R athregd-5.11.0-34 /usr/src
dkms install --no-depmod -m athregd -v 5.11.0-34 -k $(uname -r)
Stop any connections or hostapd daemons running on the interface, then remove the modules, check that the new module built with dkms is installed, and re-load the driver module. For example, for ath10k (as root):
modprobe -r ath10k ath10k_hw ath ath10k_common
depmod -a
modinfo ath | grep filename # should show new dkms location
modprobe ath10k