Reply 600 of 1069, by Maelgrum
(discrete) V4.16 looks like it has some valid data in 0x1800-0x1FFF area, but it is has not.
Data in 0x18XX is the same as in 0x19XX and so on. it is just copy of valid ROM from lower region - some address decoding artefact.
So it is 6k ROM.