It wasn’t much for a bootlog this log?
Maybe the USB start of initramfs method used for Edgerouter 4 works since the SoC seems to be the same family?
https://forum.openwrt.org/t/support-for-ubiquiti-edgerouter-4/45617/19?u=flygarn12
Just skip the copy systemupgrade part and only run the initramfs part.