Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series1/EFR32BG12P/EFR32BG12P232F1024GL125/ETM/ETMDEVTYPE#0x0
CoreSight Device Type Register
Trace Source
Processor Trace
https://github.com/cmsis-svd/cmsis-svd-data