Can anyone tell me how to do that. i read in the forum that it should be possible.
But i dont get it working.
Every time i swap the prg and chr files of a .fds image with a Nrom prg and chr the disk boot but nothig happens.
Can some explain me ?
An nrom game expects to have full control of 8000:ffff, where as FDS has prg ram at 6000:dfff and a fixed FDS bios at e000:ffff. Besides the relocation, this means that you don't control the vectors directly. (You can have the bios hand off to your vectors, but this requires a particular ram write).
Converting an NROM game to an FDS image is going to require code modification in general.
Code modification for the FDS's different runtime environment is part of why the minus world in SMB1 (FDS) isn't the same as the cartridge version's repeating 7-2; it's actually
beatable in under two minutes.
Besides needing to disassemble and reassemble the entire program ROM to move it from $8000-$FFFF to $6000-$DFFF you'll need to make some modifications as the FDS BIOS expects certain ram locations to contain certain values. Shouldn't be a big deal compared to fully disasm and reassembling the program rom.
There are also some information in
this thread. I think these two threads can be merged.