This phone is unlocked, everything works except my T Mobile sim. I have used the unlock guide iPhone unlock OS X 4 part. From what I gather, unlock has been done too many times and now something is wrong with minicom (?). I also see advice on entering some commands in "terminal."

This is where I loose it. Terminal? - is that a program to load from installer? Then what?

Is there a way to restore the minicom?

Please, advice needs to be basic. Thanks.