The newest version of a BIOS will always have all the previous version updates coded into it; so you can go from say F4 to F8 without issue.
Gigagbyte a number of Flashing tools. Probably the best one to use is that which is already built-in to your board, Q-Flash.
1). First off, get a USB stick that is formatted to FAT32.
2). Download the BIOS from Gigabyte and save to the USB stick.
3). View Parts 1 and 2 of this video! Although the motherboard is different, the way to use Q-flash is the same.
part 1
part 2
4). If you tweaked any settings, you will have to re-enter them on the newly flashed BIOS, so if this is the case make a note of any changes you made previously.
5). Now flash your BIOS!
6). MOST IMPORTANT!!!!!!!! Let us know how it went.
(Note this- Gigabyte is very cool in that there is an easy way to get back to your old BIOS in case of a Flash failure. This is what would be done (don't worry, you won't need this info):
1. Shut off the power supply using the switch on the back of the PSU, wait 10-15 seconds.
2. Press and hold the case Power On switch, then while still holding turn on the power supply from the switch on the rear.
3. Still holding the case power on switch, the board will start, once it does release the case power on switch and shut off the power supply via the switch on the rear of the unit. (Do the latter two parts as quickly as you can once the board starts)
4. The board will shut down.
5. Turn the power supply back on using the switch on the rear of the unit.
6. Turn on the motherboard by pressing the case power on button.
Once the board starts this time you should see the Gigabyte splash screen, or POST page, then the Auto-Recovery from Dual BIOS will kick in. You will see a checksum error, and then recovery from BACKUP BIOS will begin. Once it is done reboot your machine and enter the BIOS and load optimized defaults then save/apply/reboot back to BIOS.
Now you are done, and will be using whatever BIOS was in your BACKUP BIOS, From there you can attempt whatever you were previously trying, or update your BIOS to the latest version.)