This solves about 90% of all compatibility problems with repacked roms, since issues usally come from exheader settings. You don't need to waste time tweaking RSF files anymore. Get any good RSF file and you just have to set the obvious settings, like BasicInfo, CardInfo and Options. Leave the rest as is and build with any -desc template. Inject the original exheader and you always get a flawlessly repacked rom.
It can also make any rom work from the SD and spoof firmware requirements as if the game was made for v4.0 (won't make the most recent games work though).
It's a command line tool but double clicking the exe will also work.
This method was originally discovered by ground, but it takes a bit of work to be done manually, so I made this crappy thing. I also added a new feature: it can make any game work from the SD card, but only if your rom isn't encrypted.
It works via command line, so you can include it into your batch scripts but you can also double click the exe and it will ask you for the files.
(Remember you need to extract the exheader with ctrtool. If you dump it with 3DSExplorer it won't work)
Update 1: Now it checks if it's a retail rom; Doesn't use msg.exe anymore;
Update 2: Supports NCCH files. Changed bat example because -ccitocia option is buggy (thanks VerseHell)
Update 4: Supports firmware spoofing, so more games can run on the CFW's 4.X NAND. Any game that works with Gateway's firmware spoofing should work in the CFW as well. Thanks, Riku, for the idea.
Update 5: Only offfer fw spoofing if the selected rom requires it.
Update 6: Fixed some little stuff and disable exheader's "SD App" flag if the "-sd" switch isn't used
Example: here's what I used to repack Animal Crossing into a functional CIA file:
Code:
..\makerom -f ncch -target t -desc ecapp:3 -rsf gw.rsf -exefslogo -romfs extracted\xored_romfs.bin -exheader extracted\xored_exheader.bin -code extracted\exefs\code.bin -icon extracted\exefs\icon.bin -banner extracted\exefs\banner.bin -alignwr -o ANIMALTEST.CXI ..\exinjector -rom ANIMALTEST.cxi -exheader extracted\xored_exheader.bin -sd -fwspoof ..\makerom -f cia -target t -content ANIMALTEST.cxi:0:0 -o ANIMALTEST.cia