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Author Topic: Mapper 23 rom expansion.  (Read 1 times)
aishsha
Guest
« on: June 24, 2010, 06:32:00 pm »
It's Konami VRC2 type B mapper and the original rom is 256kb. Well, I have some problems with expanding this one for the second Goemon 2.
1. Nflate doesn't work.
2. Usual manual expansion (doubled space at the end of PRG and copied last 2 banks).
3. Reverted expansion (doubled space in the beginning of prg with 2 last banks copied) seems to work, but the original text in the game doesn't load.

Has anyone tried expanding this one? As strange as it is, quite common mappers of both Gaidens expand like charm...
KingMike
Guest
« Reply #1 on: June 25, 2010, 12:31:10 am »
According to Disch's mapper documents, VRC2 has a 128KB PRG limit (4-bit register (max 16 banks) x 8KB).
VRC4 (used in the Goemon Gaidens) has a 256KB PRG limit (5-bit register x 8KB).
Both sound like they have a 256KB CHR limit (256 x 1KB).
« Last Edit: June 25, 2010, 10:19:14 am by KingMike »
aishsha
Guest
« Reply #2 on: June 25, 2010, 10:27:34 am »
Too bad as they already use compression...
Dwedit
Guest
« Reply #3 on: June 25, 2010, 10:35:35 am »
How about simply doubling the entire 128k of PRG?
aishsha
Guest
« Reply #4 on: June 25, 2010, 10:49:19 am »
Quote from: Dwedit on June 25, 2010, 10:35:35 am
How about simply doubling the entire 128k of PRG?
The indexing there is quite a complicated story - I am not sure I'll be able to use that free space, if I have any...
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