Well, I have read it and think I understand.........

At the moment my K810-firmware is R8BF003, but when I flash it I can instead use R8BA024 firmware files?

I have found these files in the downloading area which I suppose will work together:
K810_R8BA024_MAIN_GENERIC_SM_RED53.rar
K810_R8BA024_FS_EUROPE_4_RED53.rar
HB1-06_Gen_CDA102568_13_R8A_GENERIC_EUROPE_4.zip

If I follow the procedure in Flash K800 CID53 with K810 software CID53 (for begginers) - Top Sony Forums, but using the three files above, I should end up having a debranded phone with R8BA024-firmware and Norwegian language. Am I correct?

I imagine I will have to unlock the phone after I have completed the above, right?