Homebrew Editing DSiWare roms

[Deleted User]

So recently I've decided to look into a small DSiWare app that I'd like to translate. I have the .nds file, and it runs in no$gba as well as on my 3ds when converted to a CIA. The .nds file appears identical to a regular NDS rom, file system and all.
However, while I can unpack it fine, it doesn't seem to repack correctly (using dsbuff v1 final). I first tried to edit the NFTR file that had the font, but after attempting to repack it, no$gba complains about the WRAM. So I unpacked the original, unmodified rom, and then repacked it with dsbuff, and I got the same result.
Does anyone have any knowledge in this area? The repacked rom is 10mb, while the original is 10.5, so I think that might have something to do with this.

 

[Deleted User]

So I decided to forget about unpacking the rom and just tried to edit it directly in a hex editor. I changed a few bytes in the nftr file (contains the font), and tried to run the game in no$gba AND on my 3ds. no$gba didn't give any error this time, it just hung on a white screen. My 3ds, after packing the .nds into a .cia, also froze on a white screen.
This confused me, so I went back to the rom and changed ONE byte. Then I tried it on no$gba and my 3ds, and I got the same result.

Now I might be wrong, but don't the TWL_FIRM patches that were built into Luma a few months back allow DSiWare to be edited? I'm thinking this might be the issue, but that still doesn't explain why no$gba doesn't work. (then again it could just be because of its poor DSi compatibility)