[coreboot] coreboot on Chromebook octopus/casta/bluebird with u-boot payload - blank screen

[James Feeney]

Ok, I finally flashed this coreboot.rom to the Samsung Chromebook 4, octopus/casta/bluebird, after disconnecting the battery and:

$ flashrom -p host --wp-status
$ flashrom -p host --wp-disable
$ flashrom -p host -l layout.txt -i BIOS  -w coreboot.rom
$ flashrom -p host -r cbimage.bin

with

$ cat -A layout.txt
00001000:00f7efff BIOS$

where flashrom says

FREG0:  Flash Descriptor region (0x 0000 0000 - 0x 0000 0fff) is read-only.
FREG5:  Device Expansion region (0x 00f7 f000 - 0x 00ff ffff) is locked.

Now, pressing the power button lights the display backlight, but that is all.

There is no u-boot prompt, though I have no experience with what to expect here.

Any suggestions, please?

Thanks
James