Openchrome

[Yioryos Asprobounitis]

I compiled the openchrome driver from svn (r902) in Ubuntu 10.4 LTS and has this strange behavior: 
When I boot the XO-1.5 with the OS from the external SDcard works fine, however when is booted from the USB stick the driver (with the same OS) segfaults!?
The Ubuntu driver works OK and my previous attempt with r886 is OK too. 
I can understand that this can be an openchrome, ubuntu, or voodoo (...) problem, but I was wondering if people with a better understanding of the XO-1.5 hardware have any idea that may focus my hunt a bit.
Thank you.