3GS All Original: Help with UL/JB Sequence Please

[zeppy]

For last few days I have spent most waking hours on the net and forums related to info to get my 3GS ready to for a TMob sim card & buy sim card and plan at my local TM store.

My iPhone 3GS:

phone was manufactured 32nd week of 2009
firmware version: 3.1.3 (7E18)
baseband version: 05.12.01 (unlocked baseband type)

After reviewing a tutorial at iclarify I am planning to use redsn0w_win_0.9.6b6 to:

Update my 3.1.3 iOS with downloaded file: 4.2.1 (3GS): iPhone2,1_4.2.1_8C148a_Restore.ipsw

I will leave my baseband version: 05.12.01 untouched and install only cydia to jailbreak it.

Next, I would use UltraSn0w via cydia to unlock the 3GS by accessing the ultrasn0w repo. in cydia.

Then, to use unlocked phone on TM GSM network I was going to use SpookeyET's posted t-mobile_us_ios4.2_1.3.0.ipcc file.

Head to store and purchase a TMob sim card was next step and buy a plan (family plan) and go from there.

Would any of you please review briefly the steps above and Add In or Comment on anything I might have missed and/or overlooked?

Any and All is Welcome and Thanked in Advance!

zeppy

[nebo1ss]

If you can get access to a MAC use pwnage tool to create and restore to custom 4.1.

Snowbreeze is a very buggy tool, only use it if you do not have access to a MAC.