Useful external tools for NDS ROM Hacking

Specs Info

• GBATEK NDS Reference

Emulating

• DeSmuME

Modifying

• Crystaltile2(Translation incomplete, can be unstable and crash at times, but still very much usable and extremely useful)
• Tinke(old, no longer supported. more info on the linked page)

Reverse-Engineering

• Ghidra with the NTRGhidra Extension
• No$GBA(Interface is not the best, but it somewhat works)
• Nitro Debugger(it's old and lacks clarity in how you're supposed to make it work)

Info on file types

• BIN: Binary file. Default file type. Used to store any kind of data(from code to graphics to dialogue text).
• SDAT: Sound Data file. Can be opened with Crystaltile2 (or VGMTrans, apparently)
• VX: movie file. Has not been decoded yet(this discussion and this discussion seem to be about as much as it is known on how the files work)

Mega Man ZX Advent only

• NBFC: Nitro Basic File Character
• NBFP: Nitro Basic File Palette
• SRL: self-contained ROM. Contains ndsheader, arm9, arm7, bit-filled fnt, and banner.
• AHX: audiovisual effect file.

Note

The game contains files that are named after its areas(example: a01.bin for area A-1, l01.bin for area L-1, x02.bin for area X-2). Those files contain data that is directly related to the corresponding (sub) area(l01.bin contains graphics for stuff in L-1 and x02.bin contains the graphics for stuff in X-2). Most of that data, however, seems not to be graphical. It is therefore possible that the files contain the game's tile data for each room in the (sub) areas.

Other

https://gbatemp.net/threads/gbatemp-rom-hacking-documentation-project-new-2016-edition-out.73394/ https://gbatemp.net/threads/how-can-i-see-the-code-in-a-nds-file.629210/#post-10110225 https://www.starcubelabs.com/reverse-engineering-ds/ https://wiki.vg-resource.com/Nintendo_DS