Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series1/EFR32MG12P/EFR32MG12P433F1024IL125/RMU/LOCK#0x0
LOCKKEY=UNLOCKED
Configuration Lock Register
Configuration Lock Key
0 (UNLOCKED): undefined
1 (LOCKED): undefined
https://github.com/cmsis-svd/cmsis-svd-data