Hey there, when I look for wifi on my raspberry pi 4, I can only find 2.4ghz bands. I tried raspbian and it was detecting 5ghz just fine, but when I go back to manjaro it doesn't recognise it. I have properly set my country code and even tried different desktop environments to no avail. (If it helps I use KDE mainly)
If you can access your router settings set the 5 GHz chanel to 36 or 40. Sometimes lowering the bandwidth helps as well.
I had this problem as well, my raspberry pi 4 couldn't see my 5GHz wireless AC network on band 157 when I installed Manjaro 19.12. I found out that the ARM edition of Manjaro did not have the
crda packages installed by default. Once I installed those two packages, I set the CRDA domain using
sudo iw reg set US and I could see my network.
I also uncommented my country code in the
/etc/conf.d/wireless-regdom so that the settings persisted and updated the
/lib/firmware/brcmfmac43455-sdio.bin wireless firmware file with the new one for the Raspberry Pi 4 for improved reliability as mentioned here . Hope that helps.
Good catch. I get so used to those packages being installed by default on other editions that I never expect they will be missing.