There is nothing illegal or wrong with modifying any of the code to suit your needs. The only requirement is that you call IFI's functions as appropriate. You may modify main.c, ifi_utils.c, ifi_startup.c
, or any other source file.
Now, your skill level is more likely a hinderence. I would imagine that 99% of the people here wouldn't dare touch ifi_startup.c. (The other 1% is Kevin Watson.
) Why? It involves initializing clib, clearing memory, and a few other low-level things. Half of it is written in inline assembly. I've only perused it a few times, nevermind modifying it.
As for the original question: modify main.c until you turn blue! Just be ready to post a lot of code when it doesn't work.