Sorry for the late reply. Life keeps me busy!
I can now
confirm that the adapter
works perfectly fine in my A600! My conclusion is that the large pins I used have caused some permanent damage to my A2000 ROM socket. I will replace the socket with my adapter, and I guess that will do the job.
The design has given me an urge to do something more 21:st century -style... Maybe a flash-based dual ROM (internally upgradeable kickswitch).
However, I have a completely different (Amiga-)project at hand, that takes all my free time right now. I will post info about it once we (me and my fellow co-constructors) come to a point we find suitable to present to the public. But rest assured; It will blow you away!
/Eriond