Jailbreak iPhone - Crashes after Upgrade from iOS 3.1.2 to 4.3.3 - Stuck in DFU mode

I needed to update my jailbroken iPhone to iOS 4 in order to use a number of apps that insist on this version of firmware in order to run.

My iPhone was running well on iOS 3.1.2 with jailbreak and Cydia. I used Blackra1n to create custom firmware to apply. Unfortunately this failed with various iPhone errors via iTunes and became stuck in a DFU loop.

Iphone error 1601, error 3984, error 1600 and error 28 on iTunes.

I tried various steps to attempt to recover my iPhone from the DFU mode but without success. Whenever plugged into the PC via USB it was detected by iTunes as being in recovery mode and to attempt recovery. This was tried with both the custom firmware (shift and click recover) and finally with the Apple firmware at iOS 4.3.5, none of which were successful.

The iphone is now with a local Medway/Chatham broken iphone repair shop to attempt to recover it. I'll post an update and recommendation if the work is a success!