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04-25-24 07:46 AM |
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| 0 users currently in ROM Hacking | 3 guests |
| Main - ROM Hacking - Expanding a ROM that has more than 16K PRG-ROM? | New thread | New reply |
| RetroRain |
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 Fuzz Ball Level: 66 Posts: 622/994 EXP: 2437961 Next: 23890 Since: 09-30-07 Last post: 1934 days Last view: 956 days |
I'm asking this question, because honestly, I haven't ROM hacked in quite a while, that I actually forgot! 
It's true, if you don't use it, you lose it. Let's say the NES game has 20 16K banks. I want to expand the ROM (double the size). I know how to do this. I just don't remember where to put the expanded space. I tried putting it after the header, but the game won't run. I tried putting after bank 1 and bank2, the game won't run. I can't seem to find a document on this either. Sure, there are documents on NES ROM expansion, but they don't seem to tell you where you put the space in a ROM that is over 16K. For example, TFG's document covers Donkey Kong, and Donkey Kong is pretty easy to expand. So is Super Mario Bros, because they both have 16K PRG-ROM banks. So I remember seeing the free space in the middle of the ROM. Thanks. ____________________ My YouTube Channel |
| snarfblam |
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 Tektite Level: 18 Posts: 50/54 EXP: 26408 Next: 3489 Since: 03-10-12 Last post: 3869 days Last view: 2819 days |
This depends largely on the mapper. You also need to consider the structure of the ROM: many games have CHR ROM after the PRG ROM. If you name the specific game you want to expand, it's easier to give an exact answer.
With MMC1 and UxROM (and others) the last bank is typically fixed. I expanded Metroid from 8 banks to 16. This necessitated copying bank 7 in the original to bank F in the expanded ROM. The result was that banks 0-6 were unmodified, 7-E were mine to use as I saw fit, and F became the fixed bank. With a game like SMB, you also need to make sure the CHR ROM stays at the end. That means that the last 8kb from the original ROM needs to be moved to the end of the expanded ROM. |
| RetroRain |
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Fuzz Ball Level: 66 Posts: 623/994 EXP: 2437961 Next: 23890 Since: 09-30-07 Last post: 1934 days Last view: 956 days |
I figured out the problem I was having. Apparently Megaman 4 can't really be expanded, because it is already at the maximum size for the mapper it uses.
Thanks for your help anyway. ____________________ My YouTube Channel |
| Insectduel |
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 Hammer Brother Level: 68 Posts: 801/1069 EXP: 2687511 Next: 41289 Since: 02-16-08 From: Insectduel's office Last post: 1256 days Last view: 1255 days |
Any idea how some games or pirated games like Pocket Monsters Yellow on the NES are more than 1,024 of rom size? |
| infidelity |
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Fuzz Ball Level: 66 Posts: 362/968 EXP: 2367837 Next: 94014 Since: 05-24-07 Last post: 957 days Last view: 813 days |
By a mapper that supports 64k for both PRG/CHR-ROM. |
| Chaobomr |
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 Buster Beetle Banned: Spammer takeover? Level: 45 Posts: 14/467 EXP: 638704 Next: 21460 Since: 05-07-13 From: The dirty south Last post: 3479 days Last view: 3477 days |
Posted by Insectduel Maybe since they're pirated, they don't need to adhere to NES standards? ____________________ Sorry for the stupidity. That jerk will be dealt with in the most insane way possible. |
| Pikachumanson |
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Newcomer Level: 7 Posts: 6/6 EXP: 937 Next: 511 Since: 03-04-13 Last post: 3972 days Last view: 3950 days |
Hence why those use weird mappers. Like the Nanjing mapper used in Ff7 |
| Main - ROM Hacking - Expanding a ROM that has more than 16K PRG-ROM? | New thread | New reply |
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