[coreboot] Group demographics

[tturne at codeaurora.org]

On 2017-03-24 17:42, Julius Werner wrote:
>> * Google's recovery manifest (from linux_recovery.sh) can pull a
>> recovery image for a specific product, I have yet to find
>> depthcharge as a payload
>> * Obviously I haven't pulled all of the recovery images, but have
>> looked at ~10
>> * those interested in recovery image,
>> /usr/sbin/chromeos_firmwareupdate --sb_extract yields a bios.bin
>> file that cbfstool can parse (i.e. is a coreboot.rom file)
> 
> All non-x86 Chromebooks that use coreboot also use depthcharge. What
> exactly do you mean when you say you can't find it? If you parse
> bios.bin with cbfstool print, you should see a "fallback/payload"
> file... that is depthcharge. (coreboot always requires the payload to
> just be called "payload" in CBFS, regardless of what it actually is.)
> You can extract it and run 'strings' on it to confirm.

This was my understanding (Depthcharge being used as payload for all 
recent Chromebooks).
What led me to question this understanding was:
  * limited number of libpayload config files in coreboot source tree
  * chromiumos build tree explicitly setting CONFIG_PAYLOAD="n" for all 
coreboot boards
  * u-boot.dtb file being present in all bios.bin files I looked at from 
linux_recovery.sh manifest (including Kevin)

As fallback/payload is compressed in bios.bin, I'm not sure what strings 
will provide.
I did run strings on bios.bin (as well as looking at it in hex editor) 
and found nothing
explicitly suggesting depthcharge (or u-boot for that matter) was the 
payload.  I made
assumption u-boot was payload based on presence of u-boot.dtb file in 
bios.bin.

As has already been explained in this thread the coreboot build within 
chromiumos tree does not include
building payload, this is a later step.  My work to date has been solely 
within confines of coreboot
build tree and directly generating depthcharge, etc. so this deferred 
building of the payload came as a surprise.

I welcome pointers to online documentation (either coreboot or 
chromiumos) that more clearly discuss coreboot inclusion within 
chromiumos build and development cycle.

Thanks to all who have contributed to my current level of knowledge and 
I know I am just scratching the surface.
Cheers,
T.mike