Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/STMicroelectronics/STM32F427/OTG_HS_GLOBAL/OTG_HS_GRXFSIZ#0x0
OTG_HS Receive FIFO size register
RxFIFO depth
https://github.com/cmsis-svd/cmsis-svd-data