What creates a locked bcu

How can you diagnose a locked bcu with a nanocom evo.

Can you change the settings in a locked bcu or save a file of bcu settings from a locked bcu with a nanocom evolution.

If you saved a file of settings from a locked bcu, to an unlocked bcu would this result in the unlocked bcu becoming locked.

While the BCU is locked it will not let the tester to work with it for safety reasons...you have to remobilise it with EKA code to gain communication with any tester