A couple of days ago my iPhone 3g (BB 6.15, 4.2.1, JBed with redsn0w) started playing up and was running very slowly, so I tried to downgrade to 4.1 to see if that would help, it didn't so i tried to get back up to 4.2.1, and now i'm completely stuck. I#ve tried restoring to 4.1 and a custom 4.1 from pwange, and the same with 4.2.1, and tried just with redsnow, or the combo of redsn0w and custom IPSWs. My phone seems to be always in DFU mode, whatever I do I either get error 21 or 1600. Occasionally the screen goes white. Just wondering if anybody got in this situation before and if theres any way out!