[coreboot] Chromebox debugging.

Kyösti Mälkki kyosti.malkki at gmail.com
Fri Jan 17 15:51:49 CET 2014

On 01/17/2014 01:01 PM, Timothy Potter wrote:
> Hi,
>    I'm trying to get Coreboot with SeaBIOS running on a Chromebox. I
> followed the page about compiling Coreboot for a Chomebook 550, assuming
> they are similar in some respects.  Unfortunately none of the builds have
> booted. Just the blue power light comes on at best.
>    I'm wondering if anyone knows which is the USB Debug Port or the pin out
> of the LPC bus connector?  I've got one of those cheap Mini PCI Express
> POST diagnostic cards but can't work out how to wire up.  I've also got an
> old Android phone with the ECHI debug gadget compiled into the kernel. I've
> tried connecting that to every USB port on the Chromebox but never get any
> output.
> Hope someone can help.
> Cheers,
>    Tim.

Hi Tim

Did you apply the two patches for EHCI gadget available here:

Try this without Chromebox first: Connect phone with any normal USB 
host. Run lsusb -v on the host to verify your Android exports USB debug 
descriptor. Then post system logs from both sides of the connection.

Now for the physical USB port to use. If you can boot your Chromebox 
with the original flash image, a working port should appear as "usb 
1-1.2" or "usb 2-1.2" in the system log when you connect any USB device.

For coreboot configuration with Intel platform, HCD_INDEX=1 maps to 
0:1d.0 and HCD_INDEX=2 maps to 0:1a.0. It's reversed order, like in the 


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