www.makemkv.com

Show your MakeMKV drive information.
But I think you can flash directly to WH16NS60 1.02MK.

Edit:
Sorry I've read your model wrong. Of course is the BH16NS40 with NS51 flashable.

You don't need a firmware backup. With the original LG firmware auto updater you can get your drive back to 1.05 ...

Bought an LG BH16NS40, FW 1.05, SVC CODE NS51, manufacturing date 2024 October

Now I cannot find this drive in post#1 exactly but reading https://forum.makemkv.com/forum/viewtopic.php?t=25901
I see user had success with flashing HL-DT-ST-BD-RE_BH16NS40-NS50-1.03-NM00000-211711201943.bin

1 - can I ...