Doesn't this one work? I can't think how an "atmega328_pro" would differ from another 328p board... optiboot-nrf24l01/optiboot_atmega328_pro_8MHz.hex at master · nschurando/optiboot-nrf24l01 · GitHub
Doesn't this one work? I can't think how an "atmega328_pro" would differ from another 328p board... optiboot-nrf24l01/optiboot_atmega328_pro_8MHz.hex at master · nschurando/optiboot-nrf24l01 · GitHub