The Earliest A2000's were not REV 4.x Motherboards those were B2000. The First A2000 were limited release and not expandable. CBM Canada had a trade up deal for anyone with the Early revisions. There units were manufactured in Germany and didn't have the CPU expansion slot, and used the same Agnus as the A1000 the 40 Pin Package not the Fat Agnus Package and were therefore limited to 512K of Chip Ram.
I did have a 4.3 A2000. I remember swapping the agnus for the one in my A500 to get 1MB chip ram. It was definitely a square agnus as I recall cracking the socket and having to do my first wire tie and epoxy fix... Still not enough chip RAM.. Then I got the CV64/3D which really seem to make the chip RAM go a lot further.
That 2000 worked really well(for being such an old dog), but even back then it was already pretty brittle and tarnished like it had been run in a really harsh environment.
