Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series0/EFM32HG/EFM32HG308F64/CMU/USHFRCOTUNE#0x0
USHFRCO Frequency Tune
Oscillator fine frequency adjust
https://github.com/cmsis-svd/cmsis-svd-data