MIN_BIOS_SIZE fell from 4 MB to 2 MB (BiosTools.cpp:16), which is what
admits the Namco System 246/256 COH-H chip dumps: those are 2 MB where a
console image is 4. The profile still declared the old floor, so it
described a gate the code had stopped applying.
Three changes travel with it. A COH-H board is region 11 rather than 8.
Its description is built from the EXTINFO serial, because Sony left the
version and date fields identical across those BIOSes, and the three
serials the code names resolve to System 256, System 246 Rack C and the
COH-H board. The ROM window is zero-filled before the read so its unused
upper half cannot retain the previous image.
The picker follows: .7d and .8g are accepted extensions, r27v1602f a
name hint. Both dumps are already in the collection, byte-identical to
the r27v1602f members of the MAME sys246 and sys256 sets, and the .7d is
the same content as 246C.bin, which Redump catalogues as Namco System
246 Rack C with the very serial the new code maps.
97 refs, all anchored, pin moved to the revision they describe.
Abdessamad Derraz