[SeaBIOS] Problems booting USB's on Chromebook Pixel 2015

[Kevin O'Connor]

On Tue, Aug 04, 2015 at 12:31:35PM +0100, Paul Hurst wrote:
> Hi there Kevin,
> 
> Hope you are well.
> 
> I am running a 2015 Chromebook Pixel LS and I'm wondering if you could
> possibly help me as I'm at my whits end :-)
> 
> I have enabled developer mode and legacy boot/usb boot using the commands
> readily available on Google but whenever I try to boot from any USB stick
> (I've tried USB 2 and 3), The screen just corrupts and the machine appears
> to hang.

It is odd that you are seeing screen corruption.  Did you try
different Linux distributions on your USB sticks?

> I know its running SeaBios as it tells me after I have pressed CTRL+L and
> it then offers me a boot menu with my devices correctly listed but its
> after that where the corruption starts.
> 
> Completely by fluke on one of my linux usb sticks, I removed it and
> reinserted it while the corruption was on screen and that did actually
> allow the boot but obviously this isnt good for my USB integrity.

If you can get into Linux from SeaBIOS then that should be enough to
obtain the SeaBIOS "cbmem" debug log.  To do this, you'll need to
download the coreboot source code (see http://coreboot.org/ ) and then
build the tool in the 'util/cbmem/ directory.  Then run "cbmem -c"
under Linux (booted via SeaBIOS) and forward the full log to this
mailing list.

Getting the SeaBIOS debug log is the next key step to figuring out the
problem.

> I do hope you can help,  I found your email via a google search as someone
> else seems to have had the same issue but there where no fix instructions
> that I could find.
> 
> Finally,  I've tried to see if its possible to update/re-install seaBios
> but there's nothing i can see online for beginners such as me.

It is possible to update seabios.  I've done it on my acer c720
chromebook.  I don't have a pixel, but I imagine the steps are
similar.  It's possible to build seabios directly from source, create
a rom using coreboot's cbfstool, and install it using the flashrom
tool that comes with chromeos.  I also understand that there are some
scripts that automate it (eg, http://johnlewis.ie/ ).

-Kevin