With OpenWrt 21.02.1 on the Raspberry Pi CM4, You may have trouble connecting to the higher 5 GHz channels. For example, I was able to scan for and connect to an 802.11ac wireless network on channel 44 but not on channel 153. The logs were also flooded with
daemon.warn wpa_supplicant: wlan0: Failed to initiate sched scan.
Updating the firmware files in
/lib/firmware/brcm/ fixed this problem for me. The latest firmware files can be downloaded from the linux-firmware repository:
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/plain/cypress/cyfmac43455-sdio.bin (rename to
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/plain/cypress/cyfmac43455-sdio.clm_blob (rename to
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/plain/brcm/brcmfmac43455-sdio.raspberrypi,4-model-b.txt (rename to brcmfmac43455-sdio.raspberrypi,4-compute-module.txt)
That works for OpenWrt 21.02.1, but not working for OpenWrt 19.07. Is there any patches for OpenWrt 19.07 working for this? Thanks.