Let me explain everything before I ask questions. I have t iphones 3gs currently running 5.0.1, they both have 06.15.00 baseband,. I bought one jailbroken and the other I did it myself using redsnow.

One of them can not connect to cydia anymore. I want to update to 5.1.1 because some aplications can't update anymore. I also want to downgrade my baseband to make the gps work.

If I downgrade the baseband will the gps work?

I have been reading about it. Apparently, I can use absinthe 2 (easier than redsnow) to jailbreak but I think I need to use redsnow because absinthe don't hacktivate, I don't have a att sim to activate it.

What should I useto jailbrake, Any suggestion? can I activate with a tmobile card?

I also installed itunes to do it but for some reason when I try to restore the phone itunes can't see the file because is a zip file instead of an ipsw file.

Am I doing something wrong?

I tried with a laptop with XP and also with a desktop with windows 7 x64 same results.

Thanks for your help.