I don't see the command you used to flash -- what was that? You also didn't clear the WP range (flashrom --wp-range 0,0) which has historically been needed on small core/Atom boards, but if you didn't get an error flashing/erasing then you're probably fine.
display backlight means it's booted to ramstage, since that's where FSP-S will init the backlight. It most likely means coreboot ran successfully and the payload is the issue.
How to debug? Get yourself a Suzy-Q cable, rebuild with the serial console enabled, flash via Suzy-Q, and then monitor via the /dev/ttyUSB1 serial port (CPU UART)
see: https://chromium.googlesource.com/chromiumos/platform/ec/+/cr50_stab/docs/ca... https://wiki.mrchromebox.tech/Unbricking#Unbricking.2FFlashing_with_a_Suzy-Q...
if you want to try a tested/verified prebuilt image w/Tianocore payload, you can use: https://mrchromebox.tech/test/fw/coreboot_tiano-bluebird-mrchromebox_2021062... https://mrchromebox.tech/test/fw/coreboot_tiano-bluebird-mrchromebox_2021062...
On Fri, Jul 2, 2021 at 7:10 PM James Feeney james@nurealm.net wrote:
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