Looks like the customer was trying to either unbrick the operating system or retrieve data from the phone that may have been stuck in a boot loop or forgot the screen lock.
Anyway, what needs to be done is the firmware reflash on there.
How to do it linked here:
https://updato.com/how-to/how-to-install-an-official-samsung-stock-firmware-using-odin
Just make sure you flash HOME_CSC if you want to keep data on the phone, not the non CSC one (This is at least for the S7 models and higher).