Need step by step for upgrading to 4.1 - 3GS on 3.1.2 - 05.13.04 BB

[atlzbest]

Hi All,

i am thorougly confused on how to upgrade my 3GS on 3.1.2 with 05.13.04 BB with Spirit JB on AT&T network. My 3.1.1 has code is saved in Cydia

I go on one forum and it has a different sets of warnings and risks like BB getting permanently updated, go on another and it says something else.

All i need is to run 4.1 such that i can untethered jb/unlock my phone (i travel international). I'd like the ability to downgrade so not sure if preserving my BB is really important.

Can someone please help me understand what i need and where can i download the tools?

thanks!

[babyblue_pimp]

You've got 4.1 shsh blobs saved correct?

Windows or Mac?

[atlzbest]

i dont have 4.1 shsh saved...help me understand why i need that?

windows only

[iYeow]

You have 4.1 blob, you just don't know you have it. Download tiny Umbrellla, plug your iphone and click save shsh .
Once you have your shsh saved , you can see all the shsh in TU.
Start tss server and slso highlight the corresponding shsh blob, do s shift + restore to 4.1 ipsw in itunes to update.