There is no
raspberry-firmware package in arch-arm. There is a raspberrypi-firmware which is our raspberry-bootloader package but it has the *.elf & *.dat files in /boot. So I do not know what you installed.
Their firmware-raspberrypi package has not been updated since last July and does not include the wifi / bloetooth firmware needed for the pi 400.
The new firmeware-raspberrypi package is the very latest from the RPi people and has all of their latest patches specific to the pi’s.
The issue I am seeing is that the linux-firmware is now including firmware for the wifi and it is either out of date or not what the RPi people are providing and that presents a problem where it puts it in the /usr/lib/firmware/brcm directory and the arch-arm forks puts it in /lib/firmware/updates/brcm so /usr/lib/firmware/brcm is getting picked up first.
I need to try to do some sort of work around I guess. Hopefully I can put the 3 brcmfmac43455* files in /usr/lib/firmware and they can get picked up first. 2 of the files are the same but brcmfmac43455-sdio.bin is different:
[ray@pi4 ~]$ md5sum /lib/firmware/brcm/brcmfmac43455-sdio.bin 0324fe9ce34b6c6c44cc5fd77a669d39 /lib/firmware/brcm/brcmfmac43455-sdio.bin [ray@pi4 ~]$ md5sum /lib/firmware/updates/brcm/brcmfmac43455-sdio.bin c4d098fdac7b453408341d5709481b10 /lib/firmware/updates/brcm/brcmfmac43455-sdio.bin [ray@pi4 ~]$ md5sum /lib/firmware/brcm/brcmfmac43455-sdio.clm_blob c5aeca0e33de4ae870986c517963fef7 /lib/firmware/brcm/brcmfmac43455-sdio.clm_blob [ray@pi4 ~]$ md5sum /lib/firmware/updates/brcm/brcmfmac43455-sdio.clm_blob c5aeca0e33de4ae870986c517963fef7 /lib/firmware/updates/brcm/brcmfmac43455-sdio.clm_blob [ray@pi4 ~]$ md5sum /lib/firmware/brcm/brcmfmac43455-sdio.txt 0ed2738fb42c392c60e34dedb74d0510 /lib/firmware/brcm/brcmfmac43455-sdio.txt [ray@pi4 ~]$ md5sum /lib/firmware/updates/brcm/brcmfmac43455-sdio.txt 0ed2738fb42c392c60e34dedb74d0510 /lib/firmware/updates/brcm/brcmfmac43455-sdio.txt