iPhone 3GS - downgrade?

[omnipotent*fart]

I have a 3GS that I unlocked a few months ago on 4.3.3. I had to unlock it and I think it put the iPad baseband on.

Fast forward to today and I updated it to iOS5 GM, but forgot the iPad baseband was on, and it won't activate on itself or through iTunes - the phone says it just 'can't', while iTunes says there's no SIM inserted. I bet this is baseband related, and was wondering if there was any way I could force the old 4.3.3 back on, and then be able to maybe push the original baseband back on.

If not, I'd at least like to be able to downgrade it to 4.3.x so I can use the damn thing (it's useless right now).

Any help appreciated. iTunes just gives me errors, TinyUmbrella in any state is being unhelpful (I do have SHSH for 4.3.3 saved). I've tried 4.3.3 and 4.3.5.

 

[Crystal-RX]

Not sure if there is any different with OS5 which preventing you to downgrade firmware. If not, then you can downgrade yours down to 4.1.

 

[omnipotent*fart]

So I need to just go straight for 4.1 then head up to 4.3.3/5?

I'm guessing there's something to do with the baseband screwing it up when it's verifying with Apple, and something TinyUmbrella/Cydia doesn't like when I attempt to go through that. The errors I've received include 10, 20, 21, 1643 and a couple others.

I'll attempt the 4.1 software - but will it make any difference over 4.3.x? Especially considering the iPad baseband in there?

 

[Crystal-RX]

So I need to just go straight for 4.1 then head up to 4.3.3/5?

I'm guessing there's something to do with the baseband screwing it up when it's verifying with Apple, and something TinyUmbrella/Cydia doesn't like when I attempt to go through that. The errors I've received include 10, 20, 21, 1643 and a couple others.

I'll attempt the 4.1 software - but will it make any difference over 4.3.x? Especially considering the iPad baseband in there?

For some reason, Apple still signs 4.1 fw and that the reason you can downgrade to it. However, at the end, because of baseband different, you will get 1015 error. Just use software to exit recovery and your phone will boot up normally.

As for your other question, you can go back to 4.3.3 unless you have SHSH blobs save. Otherwise, you have to go to the latest fw which Apple currently signs.

 

[omnipotent*fart]

For some reason, Apple still signs 4.1 fw and that the reason you can downgrade to it. However, at the end, because of baseband different, you will get 1015 error. Just use software to exit recovery and your phone will boot up normally.

As for your other question, you can go back to 4.3.3 unless you have SHSH blobs save. Otherwise, you have to go to the latest fw which Apple currently signs.

Aaaaaah. Thank you for the clear explanation - I'll give it a go!

 

[omnipotent*fart]

I've managed to restore it to 4.3.3 using 'PwnageTool' - my internet connection is so slow it'd take hours to download 4.1.

The phone is now working fine but it keeps denying there's a SIM installed. Under Settings > About it just says:

Network: Not Available
Carrier: Not Available
ICCID: No SIM

Everything else looks to be in order. The baseband is still 06.15.00.

Can I force the iPhone baseband back on, or reinstall that particular brand of baseband? A phone without the phone abilities is a bit sucky.

 

[Applejuiced]

U installed ultrasnow?

 

[omnipotent*fart]

U installed ultrasnow?

Yes - I had forgotten it but I've installed it and it's made no difference unfortunately. I thought for a minute it was all going to be perfect, but it's still reporting what it reported before.

The wifi seems a little more reliable now though - it kept dropping before. Obviously, that's a bit useless when you want to use the phone as a phone/text device!

 

[Crystal-RX]

If in the US and you want to use with T-Mobile sim, you need to turn off 3G.

 

[omnipotent*fart]

If in the US and you want to use with T-Mobile sim, you need to turn off 3G.

I'm in the UK. I've read I may need to reinstall the 06.15 baseband to make it work - but I've no idea how I'd do that. The option is greyed out in PwnageTool.

 

[omnipotent*fart]

I figured it out, thanks for the helpful hints guys.

The baseband reinstallation and re-applying ultrasn0w worked.