Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32f4/STM32F469/OTG_FS_GLOBAL/FS_DIEPTXF4#0x0
OTG_FS device IN endpoint transmit FIFO size register (OTG_FS_DIEPTXF4)
https://github.com/modm-io/cmsis-svd-stm32