Hi – any advice appreciated (cross posted on GZ site). I've got an iPhone 4 running the latest iOS5 beta which I'd like to downgrade to iOS 4.3.3. I've read reports that this should be possible (but maybe on earlier betas & maybe Apple has stopped signing 4.3.3 recently…?). 

I'm on a Mac & I've got the 4.3.3 IPSW. Have tried straight 'option click' on restore button in iTunes 10.5 beta and iTunes 10.3 plus tried 'option click & point at IPSW' while phone is in DFU mode – get the message 'this device not eligible for requested build'.

Tried running TinyUmbrella while doing this and it seems to get past the 'checking with Apple' phase, but then stops with either a '1600' or '20' error message… but I don't really understand what TinyUmbrella is doing, or if I'm using it correctly, and the shsh blobs are not stored for this phone.

If anyone has any suggestions I'd appreciate it. TIA.

Chris – thanks very much for the links…. unfortunately the procedure described is what I've been trying… still unsuccessfully. Although they don't state it, I believe that the method relies on the correct SHSH blobs being stored (the TinyUmbrella screen shot seems to confirm this). So I'm still stuck for a method….

Thanks, Chris – re. Tiny Umbrella – yes, but I believe you must have previously saved your blobs for it to retrieve them… which I haven't in this case. The phone I'm 'working on' belongs to a developer, but I was hoping to use a 'slightly shady' piece of s/w on it that required iOS 4.3.3.

Things can certainly be done on 4.3.5, and my latest plan is to actually put 4.3.5 on it then swap this phone with someone else who is still running 4.2.1 on their iPhone 4. I appreciate your input – it's great to know there's a community of great, helpful people here in NZ.