Used 'update-nand' to write os4 onto XO-1. With Q2F07 I get:
| Boot device: /nandflash:\boot\olpc.fth Arguments:
| Boot device: /pci/nandflash@c\boot\vmlinuz Arguments:
| <buffer@ffb5d500>:88:
| Can't open boot device
With os3 (and Q2F07) the two "Boot device" lines are followed by
! Loading ramdisk image ...
mikus