Odd the whole bank has gone, is it the same with the new gubbins you added removed? Perhaps try checking the seating of the MMU chip while you are at it. Have you checked the value/ amount with any other programs? A ram tester might be an idea.
Regarding the ROMs I'm no expert but I believe you can use the 32 pin ROMs, but need to use some additional wires to bridge some pins on the chip itself. I'm sure someone more knowledgeable on the subject can point you in the right direction. In the mean time 1.02 can be patched to perform on par with 1.04 fairly easily (Fatspeed or Bigdos and Pinhead 2.1 add most of the missing functionality, Selectric will sort out the file selector).