Hi guys. I have a 3GS (2009 week 51) with iOS 4.1, firmware 6.15.00, new bootrom. When I bought it it came jailbroken and unlocked. I've checked cydia and I have 4.1 blobs saved. I wanted to ask if it's possible to somehow update to iOS 6.1.3 and still be able to unlock my phone? Because once I update I will most likely lose network service as my sim is not original carrier. My friend also has a 3GS and he was not able to unlock his after 6.1.3 update. Also, will I be able to restore back to 4.1 with the blobs from 6.1.3?