I would like to keep my BDV11 board in its original condition, but would like to boot these extra devices: DU, MU, MS, DD. The documentation for the BDV11 implies that if you enter an unknown nemonic; (it only understands DX, DY, DK, DL) then it looks for a user ROM to execute from. The details are about that. Does anyone know anything about this? I've seen pictures of BDV11's on google that show not only the standard DEC masked ROM's installed in E48, E53 but other ROM's on the board. Maybe they are accessible via switch settings.