careful if you blindly update pi4 … pls check what update as ( Linux -firmware 20210208.b79d239-1 )
break your wifi…
if already update there 2 x fix for it …
1: downgrade to ( linux-firmware 20201218.646f159-1 ) that fix
2: " https://archlinuxarm.org/forum/viewtopic.php?f=15&t=15120&start=20 "
to downgrade
sudo pacman -U /var/cache/pacman/pkg/linux-firmware-20201218.646f159-1-any.pkg.tar.xz
If need help on how to downgrade
Hope it help someone