so I updated my iphone 3gs to ios 6.1.3 with baseband 6.15.00 i found out that my phone has a new bootrom but the 6.15 baseband did not brick my phone, as i have read before it may occur. my wifi still works but my sim doesn't. my messages are still there but there's no service all the time. what to do?? ---------- also, will downgrading the baseband give me service??