I am building evbarm64 from sources and using that, currently at 10.1, on a 8GB RPI4. Mine shows bcmgpio0 at simplebus1: GPIO controller 2838 bcmgpio0: pins 0..31 interrupting on GIC irq 145 bcmgpio0: pins 32..58 interrupting on GIC irq 146 gpio0 at bcmgpio0: 58 pins Did you install the "UEFI firmware", or not?