Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/STMicroelectronics/STM32F107xx/ETHERNET_MAC/MACA1HR#0x0
Ethernet MAC address 1 high register (ETH_MACA1HR)
MAC address1 high
Mask byte control
Source address
Address enable
https://github.com/cmsis-svd/cmsis-svd-data