mac has an app called stuffit, i think its still freeware. stuffit will do zip and rar last i checked. (or only zip =/). anyways if the format of the archive is a problem, tell me what format you can extract and i will just upload the firmware for you.
@Doom Chaos: take your r4 out, blow, and put it back in. sometimes it just doesn't make contact. mine use to freeze up on the loading screen alot until i used some compressed air in slot1 to clean it out. sometimes its just the flash kit not making contact and nothing else is wrong with it at all. if you are having contact issues a custom firmware isn't going to help that.
-another world