Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32f2/STM32F215/OTG_HS_DEVICE/OTG_HS_DIEPTSIZ5#0x0
OTG_HS device endpoint transfer size register
Transfer size
Packet count
Multi count
https://github.com/modm-io/cmsis-svd-stm32