[coreboot] Coreboot on X230 and Dualboot / How to make it work

[Martin Kepplinger]

Am 26.09.2017 02:20 schrieb One7two99 via coreboot:
> Hello,
> 
> I tried to flash the 8 MB Chip on my X230, but it didn't worked out.
> 
>> Me: what do I need to do to flash the 2nd (8MB) chip.
>> 
>> If the 1st chip contains the last 4MB of the file, I assume the
>> correct command could be:
>> 
>> dd of=chip8mb.rom bs=1M if=build/coreboot.rom count=8
>> 
>> Is this correct? If this is right I'll add this to the wiki as soon
>> as I have write permissions.
> 
> I've dd'ed the first 8MB of the coreboot.rom file with the above
> command and flashed it on the 8MB chip, but when booting my machine
> only illuminated the on-off-button for a second before it dies.
> 
> When reflashing the 8MB chip with the stock image which I grabbed
> before will bring my laptop back to life. As such it seems that there
> must be another was two flash both chips and to strip the coreboot.rom
> image.
> 
> Any ideas what went wrong?
> 
> As all howto's I've found so far, which cover the flashing of only the
> upper 4 MB Chip, the question is also, if someone has already flashed
> both chips and what (s)he did to make it work.
> 

what would you want to do? Analyse the image. If your BIOS fits in 4MB,
you really only need to flash the last 4MB, and using a hardware 
flasher,
you cut it out and flash it to the one 4MB chip. done.

The first 8MB contain the ME. So if you want to, read it, run me_cleaner
on it or whatever and flash it back. You will never need it for updating
coreboot as long as the BIOS is less than 4MB, which it easily is, say,
when you have only seaBIOS as your payload.

The wiki also contains an image file which is useful when you want to 
try
to flash from a running system in software, using flashrom. I don't 
recommend
doing that though. I can't say why, but my X230 died after flashing a 
few times
from a running Debian with flashrom. I couldn't bring it back to life 
using the
saved vendor bios image.