iPHONE 3gs "NO SERVICE" after upgrade to 6.1.6 .. HELP

[spEEdOfLiGht]

iPHONE 3gs
FACTORY UNLOCK na po
Mga boss Patulong po
iPHONE 3Gs before Version 4.3.2 Meron signal
After upgrade to Version 6.1.6 Nag "NO SERVICE na po mga master
Try ko na po Upgrade Baseband to 6.15 - NO LUCK
Downgrade Baseband to 5.13 - NO LUCK pa din po..
Pero kung gagawin ko siya na ver. 4.1 may signal po sya.. kaso lang hindi malagyan nga mga games at apps po kahit naka-Jailbreak ... VERSION to LOW .. sabi ni 3u tools

 

[spEEdOfLiGht]

up..up..up.. po

 

[FullFlash2014]

fu mo na baka at&t lang yan

BR..