Reply to Midifighter freezes after 2 minutes

I have a problem with midifighter. I have updated the firmware and set it to 4 bank mode in order to load the gratification tsi. It now works for about two minutes and then freezes. This happens every time I plug it into the USB port.
I have run the bootloader using the 4 corner method and flashed the unit using Flip, but the same thing still happens.
Is my midifighter broken? I hope not as I've already had one replaced.