This is describing the state with upstream coreboot. if you're looking for the coreboot deployed by google go to the ChromeOS branch of coreboot.
Tested with Seabios:
- patches not yet on gerrit
- usb works (all ports)
- seabios booting
- external hdmi works (w/ vgabios)
internal vga broken
- debug via serial on servo connector
How to flash the device
- disconnect battery
- disconnect power supply
- disconnect the board completely
- use a SOIC-8 clip + external power
To boot the system it's enought to plug in the battery + power supply, the system will boot.