<EmilyLitella> Never Mind! </EmilyLitella> I put the 32K SRAM board back in with the top four fields disabled. Sure enough, OS/8 booted and MEM showed 16K, which confirms my recollection that it will work with less than 32K. Then my lights came on - I had made an elementary error... I had selected the wrong MM8-AB 16K core board, the one that was jumpered for field 4-7. So there wasn't any core in fields 0-3 which will "break" OS/8. When I fired up the system with only the board jumpered for the LOW 16K core, everything works as usual. Sorry for the bandwidth... -Charles