Turn the TM 5402 'Off' using the power switch on the rear of the receiver... then press and hold down the 'Menu' button on the front of the receiver as you switch the TM 5402 back 'On' using the power switch on the rear of the receiver... you will then see the 'Loader Menu' on screen... try the 'Factory Reset' option on the list and see what happens..
There is no Menu button on the receiver, just Power and Channel Up and Channel Down?
Okay, firstly powering on with the power button pressed does nothing, however just trying something I pressed the channel up and down buttons at the same time as I powered on and hey presto the loader menu came up. Loaded the original firmware from technomate using a USB and it worked! Flashed back to stock.
So thanks for everyone's help and assistance.
When I held the power button on whilst switching on from the back nothing happened at all, tried several times and for varying lengths of time. But as soon as I held the two channel buttons on and powered up the loader menu came up, perhaps it is unique to the f3/5?