Alternate MSX system ROM's:
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DISK.ROM     - Philips (original: Sanyo)
MSXDOS2A.ROM - Turbo-R MSX-DOS 2.31 (accesses FDC directly)
MSXDOS2B.ROM - Turbo-R MSX-DOS 2.31 (CHOICE not patched: FORMAT fails)
MSXKANJI.ROM - Uses more conventional RAM as the original
MSXJE.ROM    - Corrupted variant of MSX-JE/MSX-View (64KB)
MSXVIEW.ROM  - Corrupted variant of MSX-JE/MSX-View (32KB)
MSX2P.ROM    - MSX System BIOS 3.0's first version (in 1988)
MSX2PEXT.ROM - MSX 2+ SubROM without startup-logo
MSXTROPT.ROM - Dummy version of MSX Turbo-R logo ROM in Slot 0-3
