Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Spansion/MB9BF52xT/FLASH_IF/FSTR1#0x0
register FSTR1
bitfield RDY
bitfield HNG
bitfield CERS
bitfield ESPS
bitfield SERS
bitfield PGMS
https://github.com/cmsis-svd/cmsis-svd-data