3gs 4.0.2 New bootrom unlock?

[mvpemmitt]

I picked up a 3gs with the new bootrom, made in the 30th week 2010.

It currently has 4.0.2 installed, with no shsh, I used tiny umbrella to check that. So I dont have any blobs to downgrade.

I want to use it on Tmobile so I need it unlocked.

I tried to upgrade with custom firmware 4.2.1 but now its stuck in restore mode and wont boot up. So, I am unsure if it took the 4.2.1 firmware or if it still has the 4.0.2.

I searched and couldnt find any helpful info so I am asking here.

Can I upgrade to 4.3 with custom firmware so I dont change my baseband, which is 5.13.04 and then unlock?....

Or am I screwed lol?...

I appreciate any help or direction in getting this fixed.

Thank alot!!

[i.Annie]

You can use pwnagetool for Mac or sn0wbreeze for windows to update to 4.3.1 untethered to create a custom firmware and preserve your baseband to unlock.

Note that going to 4.3.1 may cause issues for unlockers as ultrasn0w doesn't seem compatible with 4.3.1 yet. I'd recommend waiting and staying where you are now. Just jailbreak it with limera1n or redsn0w (your choice) to jb 4.0.2 and unlock with ultrasn0w from Cydia.

[mvpemmitt]

Annie, thanks for your advice.

Phone wouldnt boot and only SHSH available were 4.1 and 4.3.1 so I was able to restore to 4.1 but I think I screwed myself.

The baseband is now 05.14.02

Is there an unlock solution? BESIDES the one that changes the baseband to the ipad one? The phone still has warranty and I would prefer not to void it.

So am I right in the fact that now this phone is not unlockable WITHOUT voiding warranty?

Someone please tell me im wrong!..... Please!!....

[kaygee]

The only way to unlock right now is to update BB to ipad BB since it's been upgraded to 5.14.02.

[i.Annie]

Unfortunately once you update the baseband you can't unlock without updating to the iPad baseband.