Aporte original por: gpaps ,
My 3GS had the same symptoms after installing the ipad modem firmware, even after downgrading. Phone was rendered useless, rebooting, no wifi, not responsive, etc. Thought it was bricked for good. Desperately I did a restore as new from itunes to IOS6 and new firmware 05.16.07, now everything is working as new! Needless to say I am relieved. Now will seriously think about it before attempting to jailbreak/unlock it again.