I just debranded a PAYG K770i and have managed to get it all working after hours of reading and messing around with JDFlasher and Far.

The only problem I have is that the End Call button doesn't end calls, I have to use the right softkey. The End Call Button Brings up a menu with

New Events
Running Apps
Shortcuts
Internet

Which doesn't seem right.

As well as this I can't assign up on the DPad, it always goes to my pictures which isn't too useful for me.

Is there a recommended generic firmware?

The one I used is this one: HB1-06_Gen_CDA102568_13_R8A_GENERIC_EUROPE_4

Sorry if this is all very simple and tedious. Thanks in advance for your help.