what's the purpose of unmod it? if the purpose is to go online for Live! service, then you might as well forget it

yes, it's possible to unmod a softmodded xbox360, but once the console is modded, it's already red-flagged by MS based on the console ID, so even after you unmod it, it's still red-flagged as modded in MS database

So it's just a matter of time you received a big banhammer gift from MS after you went online

So if you wanna join the Live! service, go buy a new non-modded console