Since the iControlpad is not really present online anymore, here are the essential files available to download:
I wanted to get Fire Emblem 12 for the Nintendo DS in english. The team doesn’t provide instructions for Linux.
Install xdelta3 with a simple: sudo apt-get install xdelta3
Then the command to patch your rom is:
xdelta3 -dfs IN.nds NAMEOFPATCH.delta OUT.nds