I have upgraded my iPhone 3G from iOS 3 to iOS 4.2.1 using the iclarified Redhook for windows tutorial.
Upgrade has gone fine but I cannot get Redsn0w (v0.9.6b6) to recognise the DFU state. Every time I restart in DFU mode, I get the following error:
"No Device Detected. You probably misunderstood the instructions. Please consult Google or YouTube on how to enter DFU mode"
Please note I had problems entering DFU following the Redsn0w instructions (i.e. start from off then: hold power 2-3s, power & home 5-10s, then home 13s) as these do not work from power off on my iphone 3g. If my iphone is off and power button or power & home button are held, iphone immediately starts in recovery mode (with icon).
I can enter DFU (black screen) by having phone on, holding power button and slide power off on screen, I then release power button 5-6s after phone has switched off (per DFU instructions on google utube etc), phone enters DFU mode but not picked up by redsnow
Any suggestions welcome