Hi 5cott
Perhaps your bp / flex version should help solving the problem (or trying to understand it

)
[GSMA910BTUK042]
Please have a look at this in settings menu and report it here....
Also, to complete could you give us some more details:
Does your battery is good and does charging works ?
[I used an external charger and managed to fully charge the battery. This got the phone up and running. Still won't charge. Will try reflashing]
Does charging work, especially when the "bad battery" message is here?
[No]
Did you tried to flash another firmware?
Have you reflashed it?
Thanks.