The adapter has a PAL to do some sort of address decoding as the GVP/A2091 card only has enough address lines for a 16KB ROM (27C128). The Guru ROM is a 32KB chip (27C256). I have tried to copy the PAL but naturally it has the copy bit enabled so I couldn't copy it.
It is frustrating as the Guru rom is no longer commercially available. I'm always happy to support any hardware vendors such as Jens and Ralph but when they decide to no longer support a device, they should make things like the PAL image available to everyone so that we can at least make the adapters ourselves. 
I have talked to ralph about this at one time, and because places like softhut list them but do not have them,ralph won't release the code because he says it would undercut vendors. I explained that i contacted softhut and they don't have the guru roms but this did no good.
mech
