Downgrading jailbroken 3G Iphone from OS 4.01 to 3.1.3 or 3.1.2 without saved SHSH ?

[Paavou]

Hi guys.

I have Iphone 3G with OS 4.0.1 installed ,jailbreak-ed and unlocked and SHSH saved in Cydia. But because OS 4.0 have slowed down my phone really badly I was wondering if there is a way to downgrade it back to OS 3.1.3 or 3.1.2.
As I understand the main problem is that I don't have SHSH saved for 3.1.3 or 3.1.2 anywhere. Is there any workaround of this issue or isn't it possible at all and am I stucked with OS 4 forever?

 

[-aggie-]

You have a 3G, so it's much easier. Put your phone in DFU mode (see my sig) and then option (or shift) restore to the 3.1.3 or 3.1.2 .ipsw file you downloaded (google for download if you don't have it). Eventually, you'll get an error, so use recboot or tiny umbrella to get out of it. See here for more info:

https://forums.macrumors.com/threads/978262/

 

[Paavou]

Thank you for replay.

Just to be sure.
Can I still jailbreak and unlock it after that?

 

[f4780y]

Thank you for replay.

Just to be sure.
Can I still jailbreak and unlock it after that?

Yes, you can JB and unlock after you complete the downgrade.