Tried flashing K850i - seemed to work, but phone won't work with an Orange PAYG SIM. It will work with the old "3" contract SIM,

Identifier says:-

Network LOCKED
Operator: MULTIPLE

Did I use the right files -

K850_R1CA029_MAIN_GENERIC_SO_RED52.mbn
k850_R1CA029_FS_CENTRAL-EUROPE_RED52.fbn