Search on this forum for M55 test point.
After this is done, select Test Point on the configuration menu on Freia and select Unlock/Direct unlock no map is saved. When it asks you to press power, do so, and it should boot and unlock normally.
If the test point is not made well, it will still say Boot File is Not Accepted. Also please be careful as if you damage other parts of the board the phone could be dead...