Bpatch is universal tool for patching any binary files. This tool maybe exists for many GPL OS but I don't find it. So, I developed my own.
I developed bpatch in ANSI C with emphasis to the portability. So you can compile and use bpatch on: M$-DOS, Windoze, Linux, Epoc, EpocEmx and many others OSes. Sources are published under GPL license, so you can feel free if you want make some modifications.
Poke^Patisoners.