I created an SD card with ArchLinuxARM-aarch64-latest.tar.gz according to https://archlinuxarm.org/platforms/armv8/broadcom/raspberry-pi-4. When I boot the RPi 400 from this card, the following messages come up once:
$this->bbcode_second_pass_code('', '
board: ...
boot: node USB-MSD 4 order f41 retry 0/128 restart 7/-1
sd: card detected ...
part: 0 mbr [...]
fw: start.elf fixup.dat
net: down ip: 0.0.0.0 sn: 0.0.0.0 gw: 0.0.0.0
tftp: ...
')
The following message are repeated:
$this->bbcode_second_pass_code('', '
Trying partition: 0
lba: 2048 oem: 'mkfs.fat' volume ' v ^'
rsc 8 fat sectors 200 c-count 51145 c-size 8 r-dir 1 r-sec 32
Firmware not found
USB2[1] 400202e1 ...
USB2 root HUB part 1 init
...
')