hmm can you try warm boot? ie first boot with your classic pc bios, then warm boot into the linuxbios+adlo and all other stuff.
I tried but no success.
If you have ICE, you could try to see how far it goes. u could setup execution break point at 0x7C00 as it is used repeately during the boot.
I don't have ICE (Could you recommend one ?) . Therefore I printed post code at several point of bochs code. And I think it stop during VGABIOS execution because it works before option rom scan procedure. I think EPIA bios do something on northbridge settings which VGABIOS require. How do you think?
I found some VGA related registers on northbridge such as 0xfb register which have 'VGA Enable' disable bit. However When I enable it, strangely etherboot doesn't works and system restarted. (My boot configuration is linuxbios -> etherboot -> ADLO payload )
Hmm..
-- Adam Sulmicki http://www.eax.com The Supreme Headquarters of the 32 bit registers