DIGI CM32 - Firmware Upgarde Failed - URGENT - PLEASE HELP !

I have tried to upgrade the latest firmware for the CM32 and each time after the ftp has completed I get a broken pipe and then it fails to reboot. The last time we tried this we had to have a new unit sent as we could not get it to re-load an image from the boot loader succesfully.
I have downloaded the 1.5 bin image and tried to download it via the web gui as we tried the command line version last time and now we have a non working unit again.
Please can someone post the correct procedure to upgrade the firmware and then I can check we are following the correct procedures.Thanks