If I recall correctly, it was an MS-DOS system,
Yes.
so unless their BIOS was seriously broken,
Their BIOS isn't "broken", but it's certainly *much* different. They
weren't trying to build a PC clone.
it should run generic MS-DOS if not PC-DOS.
Definitely not PC-DOS. And there isn't really such a think as
"generic MS-DOS", except in the sense that Microsoft sold MS-DOS
adaptation kits to OEMs. What shipped to customers was always
specific to a particular kind of computer. So MS-DOS 1.25 for
the Sanyo is NOT the same as MS-DOS 1.25 for an HP 150, Tandy 2000,
or Heath/Zenith Z-100.
Of course, by the late 1980s most everyone had given up on making
x86-based machines that were not PC-compatible.