newer iPhone 3Gs downgrading

[TheRealDeal]

OK so I originally posted in the T-mobile forums:

Problem using T-mobile prepaid on iPhone 3gs

But I figured out where I went wrong.

The original instructions I had told me that as long as the last TWO numbers of the serial were less than 35 I would be OK but now I'm reading that the last THREE numbers need to be less than 135.

So I have an iPhone 3Gs with version 5.0.1 and a serial number with the last 3 numbers as 929...

I've tried everything... How do I get this thing working with T-mobile??

[monkeydance]

Post ur first 6serial...... Dont want to tell u ok to flash to ipad baseband that could brick u phone.

[TheRealDeal]

88929... I also put the phone in DFU mode and went into system profiler and double checked that it was the old bootrom which it was.

Got it working though! Here's what I did for anyone who wants to know or comes to this post looking for answers... Also I have a question regarding errors with ultrasn0w at the end.

Here's my specs:

iPhone 3GS
Version 5.0.1
Baseband 5.16.05
Serial 88929 (old bootrom)
Carrier: T-mobile prepaid

I downloaded the following:

-Pwnage tool 4.1.3
-iPhone 2,1 4.1 IPSW
-iPad 1,1 3.2.2 IPSW
-Tiny Umbrella

I first opened the file /etc/hosts and added the following to the bottom of the file:

74.208.10.249 gs.apple.com

I ran Pwnage tool to create my custom ipsw and flash to the new baseband.

I did a custom restore with the custom ipsw Pwnage tool just created. Then when the 1015 error came up I used Tiny umbrella to exit recovery mode.

Then I installed ultrasn0w on my iPhone from the Cydia app.

It's funny because ultrasn0w actually showed a bunch of errors and I thought I ran into another failed attempt like I had been having for 2 days but as soon as I returned to Cydia I got a text message which meant it worked. So as of right now I haven't touched anything cause I don't want to fix what ain't broken!

Does anyone think that will cause a problem down the line?