OK, for future reference, if you are updating the Firmware on any device, SSD, HDD, DVD that is connected by SATA it is safer to remove the other devices from the system first as sometimes, the Firmware Flashing Process can affect other SATA devices.
I'm not sure why the system won't fire up with the DVD drive attached to the GSATA Port but this could be something to do with the F8n Beta BIOS. That said, if evertthing settles down now and runs as it should, I wouldn't flash back to the F7 but just keep in mind that you could have an issue when you try to use the GSATA Ports.