i've got serial on a spectrum SAX1V1S, Sagemcom Fast5285 device.
it's broadcom, quadcore @1..8MHz.
the bootlog is at https://pastebin.com/Z4GDtzs4
sadly, i can't interrupt the cfe boot.
i welcome you to please take a loot at the log and see if you can find any hint.
thanks
Did you ever get anywhere with this? Did you try to break the boot with the hardware method?
i gave up; i dont think i tried messing with hardware.