This page will contain patches to enable certain unsupported games to work on the Dr. PC Jr. system. Generally, every unsupported game has to be hacked individually, so there is no blanket patch for all games, unfortunately.
Each patch will contain instructions about how to apply it, but generally, you will need an IPS patching program and a program to join binary files together. You can find IPS patching programs at Zophar's Domain. If you have a DOS PC, your regular COPY command will join files like so:
COPY /b file1+file2+file3 file123.
I also recommend the program "CHDIR2" for some of the batch files. Try searching for it at The Best Game Music.
There should be batch files to automate the patching process, but if you can't use it, then in general, to patch an unsupported game to work on the PCJr, you:
You will not find game ROMs on this page, so don't even bother looking!
- Make a copy of the NES ROM for safety's sake.
- Apply the IPS patch to the copy of the .NES file.
- Join the included header (.HED) to the beginning of the patched file.
- Rename the joined file to "FCxxxxxx" and run it in your PCJr.
If a game doesn't work on the PCJr, and you think it should, there could be a couple of errors in the header which prevent the game from loading properly. There are a few general fixes for some mappers.
- 0 (NROM) and 3 (CNROM): Ensure that header byte 19 (HEX $13) is set to "00" (or "0x" for CNROM games).
- 1 (MMC1): Some games require byte 32 (HEX $20) to be set to "FF".
- 71 (Camerica/Codemasters): Funny enough, Camerica games double quite nicely as mapper 2 (UNROM), so try converting a Camerica game just as it is. It should work fine. If not, then change byte $0E to "$40" and byte $12 to "$50."
If a game works, but the graphics become glitchy, the PPU Mirroring bits in the header might be set improperly. Try changing the proper mirroring bits in header bytes 14 (HEX $0E) and 18 (HEX $12).