Homebrew Romfs and Exefs

[I_AM_L_FORCE]

So I've just extracted these two files and I wanna mod them. Now what do I do?
Romfs.bin
Exefs.bin

 

[Razorzeto]

You could extract Romfs.bin with "RomFS Extractor", then use "Every File Explorer" to decompress some files and start to play with them.

 

[Hiccup]

ctrtool is probably the most comprehensive romfs/exefs extracter/packer
and a lot of "tools" are just dumbed down frontends for it