Thanks for the guide, Very smooth updated with my flashed Gigabyte HD7970 3GB, enjoy the new benefit of new firmware now
My step from El Capitan:
- Run install High Sierra to get firmware from MP51.007F.B03 to MP51.0084.B00
(not yet update to High Sierra at this point, only firmware update)
- Update OS to High Sierra to allows new firmware from Mojave
(now my OS is High Sierra 10.13.6)
- Install Mojave to get firmware to 138.0.0.0
(now got New video link speed from 2.5GT/s to 5.0GT/s with Metal supported)
Million thanks for the guide