iPhone 3GS -- iOS 5.0 -> 6.xx on 6.15.00 Baseband?

[l0gikb0mb]

Hey guys, is it possible to do this? My GF's 3GS is laying around on iOS 5 and it is incredibly slow. I'm thinking since it was the very first iOS 5.0 version, it could be because of that, and am hearing reports that iOS 6 is better performance wise.

How would I do this? She is on baseband 06.15.00, and the UNLOCK feature is needed! (Telus service on Rogers iPhone).

 

[cyber16]

First see if you have the older 3GS iphone so you can roll the baseband back, this way you can re-gain a functional GPS since 6.15.00 was from the ipad and broke the GPS on the iphone
http://www.iclarified.com/entry/index.php?enid=22652

Then, make a custom NO baseband update ipsw, restore that onto your iphone
Then complete the jailbreak and install UnltraSnow from Cyndia for the software unlock OR go to eBay and pay a few $'s for the factory unlock via itunes
iclarified has plenty of guides

 

[dextr3k]

Rogers phones are insanely expensive to IMEI unlock, in the $150 range.

You are already on the iPad baseband so you are qualified for downgrades. New bootroms are not able to install the iPad baseband in the first place so you don't have to worry about this. You will need an older version of redsn0w (I have used 0.9.14 with success) and maybe a few tries to have the downgrade take.

Then you can update using a NO_BB custom fw...