Hi,

I wanted to update to 4.0 from 3.1.2 so tried doing it with redsnow and a custom firmware that i got of some torrent. After the custom firmware update, my phone is stuck in dfu mode and TinyUmbrella, Recboot or iRecovery can't kick it out. I'm getting a totally black screen.

I used official 4.1.2 firmware through redsnow to boot theathered...the phone starts to the unlock screen but is not activated so it asks me for a valid SIM which i cannot get. Also after a while the phone goes back to dfu loop mode. The battery is charged.

What should i do? Do i upgrade to 4.2? I have these specifications

iPhone 3GS
Firmware 4.0
Baseband: 5.13.04
New Bootrom
SHSH: only for 4.2.1


Please help

We really don't support pirates here. It's been made very clear here that you need to make your own custom IPSW using pwnagetool - you cannot trust a custom IPSW from a torrent.

You have done a number of incredibly stupid things:

1. Blindly installed a custom IPSW from an untrusted source
2. Not checked if you have an old or new bootrom 3GS - this is critical for the success of Pwnagetool custom IPSW on a 3GS
3. Restored your OS without any useful SHSH on file - as a backup plan.
4. Mixed 4.2.1 "just boot tethered for now" kernel with 4.0 IPSW, plus you likely have parts of 3.x still around in your NOR as I suspect you have a new bootrom 3GS. This is a Frankenstein combination that makes your nightmares scared.

It is clearly explained on the first redsn0w screen that you must use an IPSW for the same iOS version you are currently running. It is absolute idiocy to try and mix a 4.2.1 "just boot tethered for now" with a base iOS 4.0 .

Also, how hard is it to type 4.2.1 ?? there is no iOS 4.1.2 - there never was, and will probably never be. I see this mistake every day - why is it so confusing to type 4.2.1 correctly?

My recommendation: find out if you have new bootrom 3GS. Double check what SHSH you have. Find someone with a real honest to goodness mac and pwnagetool 4.1.3

Then we might be willing to help you.