Flashing Gigabyte while avoiding "Invalid BIOS image"

BIOS/UEFI Modding BIOS Modding Guides and Problems
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This guide is for those who have updated their Gigabyte Z370, Z390 to the latest BIOS with a capsule and want to go back to an earlier BIOS but can’t such as @obz @XQJ-37 @saydji @monta990 @hukis @GHOST.CHIP

It’s possible to downgrade using Intel’s Flash Programming Tool (FPT).

For Z370 (and other 300 series mobo’s that have 22nm chipsets) you should use Intel FPT v11.8.x

FPT_v11.8.x.zip

For Z390 (and other 300 series mobo’s that have 14nm chipsets) you will need Intel FPT v12.0.x

FPT_v12.0.x.zip

Inside each archive are UEFI, DOS, Windows 32-bit and 64-bit versions, you can use the same commands for each version.

WARNING: Unlike Qflash or Efiflash, FPT will not check if you are flashing the correct BIOS to a matching motherboard so you can brick your motherboard if you cross-flash the wrong BIOS! Be very careful!

2ND WARNING: If your motherboard has any Intel Gigabit Ethernet Adapters you can overwrite (erase) their MAC address(es) with FPT causing them to no longer function! Although the MAC addresses may be recoverable it is a big hassle that you will want to avoid. You will know if you have erased them if they display 888888888788 as their MAC address.

DISCLAIMER There is always a risk when flashing the firmware of any motherboard. You must decide if you think the risk is worth it - if you don’t know how to recover your motherboard from a bad flash then I don’t recommend that you attempt a BIOS downgrade. I am not responsible for any problems that arise from your actions. While I have performed a downgrade on two Gigabyte Z390 motherboards (Z390 UD and Z390 AORUS PRO WIFI) I cannot 100% guarantee that you will not run into problems. Please read the entire guide before you even attempt a downgrade.

BEFORE YOU ATTEMPT TO DOWNGRADE YOUR BIOS YOU SHOULD WRITE DOWN THE MAC ADDRESSES OF ANY INTEL GIGABIT ETHERNET ADAPTERS IN YOUR SYSTEM.

You can find your Intel MAC address(es) several ways.

I. Boot into the BIOS and look under Settings –> IO Ports –> Intel Ethernet Connection

(also listed at System Info –> LAN MAC Address)

II. In Windows open an elevated command prompt and type “ipconfig /all” then look for “Ethernet adapter Ethernet” then “Physical Address”, some boards have two Intel adapters - you will need to copy and save the MAC addresses somewhere, you can be sure it is an Intel Gigabit Adapter by checking the description.

III. If your adapters are currently plugged into a network, Control Panel –> Network and Sharing Centre –> Change Adapter Settings –> double-click on ‘Ethernet’, then click ‘Details’ and look for ‘Physical Address’, make sure it is an Intel Gigabit Adapter by checking the description.

BIOS Downgrade Method 1: Using 64-bit FPT from a command prompt in Windows

  1. Download the correct FPT tool for your motherboard and create a folder on C Drive called FPT. Copy the contents of the WIN64 folder from the zip archive into the new FPT folder on C Drive.

  2. Open an elavated command prompt (as administrator) and navigate to the FPT folder

  3. Make a backup of your current BIOS chip using the command;

fptw64 -d bios.bin

You should see “FPT Operation Successful.” If not then you may have a BIOS chip that FPT cannot recognise.

  1. To check if your motherboard has any Intel ethernet adapters and at the sametime backup the MAC address(es) type the following commands;

fptw64 -gbe -d gbe.bin

a. There are only six Z370/Z390 motherboards that don’t have an Intel NIC, for those you will see the following;

“GbE region does not exist!”

This means you likely have either a Realtek or Rivet Networks ‘Killer’ NIC and don’t need to worry about your MAC being erased by FPT.

b. All other Z370/Z390 motherboards that have Intel Gigabit Ethernet Adapters should give you the following message;

8KB of 8KB - 100 percent complete.
FPT Operation Successful.

NOTE: If you open gbe.bin in a hex editor you can find your MAC address(es).

  1. Copy the BIOS file you want to flash into your FPT folder.

Use the following commands to flash the entire EEPROM (all BIOS regions are overwritten i.e. Descriptor, GbE, ME and BIOS);

fptw64 -SAVEMAC -f .bin

The command -SAVEMAC will retain your Intel MAC address(es) so don’t leave it out!

If you have a motherboard with no Intel NIC then you can just use;

fptw64 -f .bin

  1. Once the flash operation says it has completed successfully type the following command to IMMEDIATLEY reboot and load the BIOS you just flashed;

fptw64 -greset

Note that your PC will restart instantly without any warning as though you have pressed the reset button.

  1. Go into BIOS and check the BIOS version under System Info, it should be the older BIOS.

BIOS Downgrade Method 2: Using the DOS version of FPT from a FAT32 formatted bootable USB stick.

  1. Download Rufus and use it to create a DOS bootable USB stick with FreeDOS or MSDOS.

  2. Download the correct FPT tool for your motherboard and copy the file FPT.exe from the DOS folder in the zip archive onto the USB stick and also copy the BIOS you want to downgrade to.

  3. Boot into FreeDOS or MSDOS (CSM will need to be enabled in your BIOS)

  4. Make a backup of your current BIOS chip using the command;

fpt -d bios.bin

You should see “FPT Operation Successful.” If not then you may have a BIOS chip that FPT cannot recognise.

  1. To check if your motherboard has any Intel ethernet adapters and at the sametime backup the MAC address(es) type the following commands;

fpt -gbe -d gbe.bin

a. There are only six Z370/Z390 motherboards that don’t have an Intel NIC, for those you will see the following;

“GbE region does not exist!”

This means you likely have either a Realtek NIC or Rivet Networks ‘Killer’ NIC and don’t need to worry about your MAC being erased by FPT.

b. All other Z370/Z390 motherboards that have Intel Gigabit Ethernet Adapters should give you the following message;

8KB of 8KB - 100 percent complete.
FPT Operation Successful.

NOTE: If you open gbe.bin in a hex editor you can find your MAC address(es).

  1. Copy the BIOS file you want to flash into your FPT folder.

Use the following commands to flash the entire EEPROM (all BIOS regions are overwritten i.e. Descriptor, GbE, ME, BIOS) ;

fpt -SAVEMAC -f .bin

The command -SAVEMAC will retain your Intel MAC address(es) so don’t leave it out!

If you have a motherboard with no Intel NIC then you can just use;

fpt -f .bin

  1. Once the flash operation says it has completed successfully type the following command to IMMEDIATLEY reboot and load the BIOS you just flashed;

fpt -greset

Note that your PC will restart instantly without any warning as though you have pressed the reset button.

  1. Go into BIOS and check the BIOS version under System Info, it should be the older BIOS.

BIOS Downgrade Method 3: Using an EFI Shell

  1. Copy a full EFI shell to a bootable USB stick (it should be named BOOTX64.EFI)

  2. Download the correct FPT tool for your motherboard and copy the contents of the EFI64 folder in the zip archive onto the USB stick and also copy the BIOS you want to downgrade to (put the files in the same directory as your EFI shell).

  3. Boot into the UEFI shell and select the file system on your USB stick e.g. fs0: (you may need to use the map command to find the USB stick if you have many drives/partitions)

NOTE: You can check if you have the correct drive with the directory command “dir”, you should see FPT.efi and your BIOS file.

  1. Make a backup of your current BIOS chip using the command;

fpt -d bios.bin

You should see “FPT Operation Successful.” If not then you may have a BIOS chip that FPT cannot recognise.

  1. To check if your motherboard has any Intel ethernet adapters and at the sametime backup the MAC address(es) type the following commands;

fpt -gbe -d gbe.bin

a. There are only six Z370/Z390 motherboards that don’t have an Intel NIC, for those you will see the following;

“GbE region does not exist!”

This means you likely have either a Realtek NIC or Rivet Networks ‘Killer’ NIC and don’t need to worry about your MAC being erased by FPT.

b. All other Z370/Z390 motherboards that have Intel Gigabit Ethernet Adapters should give you the following message;

8KB of 8KB - 100 percent complete.
FPT Operation Successful.

NOTE: If you open gbe.bin in a hex editor you can find your MAC address(es).

  1. Copy the BIOS file you want to flash into your FPT folder.

Use the following commands to flash the entire EEPROM (all BIOS regions are overwritten i.e. Descriptor, GbE, ME, BIOS) ;

fpt -SAVEMAC -f .bin

The command -SAVEMAC will retain your Intel MAC address(es) so don’t leave it out!

If you have a motherboard with no Intel NIC then you can just use;

fpt -f .bin

  1. Once the flash operation says it has completed successfully type the following command to IMMEDIATLEY reboot and load the BIOS you just flashed;

fpt -greset

Note that your PC will restart instantly without any warning as though you have pressed the reset button.

  1. Go into BIOS and check the BIOS version under System Info, it should be the older BIOS.

[Edit] Any motherboards with DualBIOS may still have the newer capsule BIOS on the backup BIOS chip after you have used FPT to restore the older BIOS to the main chip.
If you need to flash the backup BIOS chip you will need to use EFIflash with the /db switch. e.g.

efiflash .bin /db

Note that this command flashes the main BIOS chip first and then the backup chip.

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