@tarcis
Your mod seems ok, correct bios volume and original pad kept intact, good luck.
It’s working now! Thanks @MeatWar
Didn’t get the unacessible_boot_device this time and no corrupt bios after a few boots.
FY’all I I used the compressed and small module from the mirror link on the main post while selecting compressed on the MMtool.
Before that I was using the small module primary link which is a different file.
Hello, first I would like to appreciate @Lost_N_BIOS & @dsanke & @ex58 - after reading 20 pages of this thread Im amazed how helpful u are Guys for the ppl.
Im writing cuz I also want so hard to downgrade my BIOS to F9 from F12, I updated my BIOS 2 days ago and I realized my CPU but mostly new GPU performance went down much…
I did many pendrives with Rufus and many Efiflash versions, and everytime I have all the time Invalid BIOS image (cant post link to photo sorry)
I would appreciate your help very much
Motherboard: Z390 AORUS PRO (rev. 1.0)
CPU: i9 9900k
Not sure right now how this patched EFI tool versions had any success, because recently Gigabyte introduced new capsule bios format in recent updates, so maybe you’re out luck if that recent update of
yours is already new method, as i’ve not seen any successful reports.
Lost is not an active forum member since January 2021.
Thank u for fast reply MeatWar.
I see, I tested combination of every bios version with every Efiflash and all the time this info: htt ps://imgbb.com/R6040wb
I bought new GPU rtx3080 and after bios upgrade to F12 performance is like -20%, and similar with CPU…
Maybe anyone know any way how to downgrade F12, I would Love You for any tip!
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
For Z390 (and other 300 series mobo’s that have 14nm chipsets) you will need Intel FPT v12.0.x
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
-
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.
-
Open an elavated command prompt (as administrator) and navigate to the FPT folder
-
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.
- 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).
- 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
- 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.
- 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.
-
Download Rufus and use it to create a DOS bootable USB stick with FreeDOS or MSDOS.
-
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.
-
Boot into FreeDOS or MSDOS (CSM will need to be enabled in your BIOS)
-
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.
- 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).
- 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
- 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.
- 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
-
Copy a full EFI shell to a bootable USB stick (it should be named BOOTX64.EFI)
-
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).
-
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.
- 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.
- 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).
- 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
- 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.
- 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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@chinobino Hello, i am currently having a modded bios for B550M Gaming, currently at bios F13c iirc, and i did have the release F13 modded, do i need to download the efiflash 0.85 that has been modded by @dsanke , or @ex58 efiflash 1.0? is @ex58 efiflash 1.0 has been modded or it’s the stock? or should i use the efiflash.exe from the bios original .zip file from gigabyte and run it on windows? which one should i use? what suffix/command i should do for flashing the efiflash? also why did you recommend MS Dos besides FreeDos? Sorry for too many questions since this mobo dont have B_Bios, and Thank you 
@Koekieezz If you want to flash a modified BIOS you should use the modified Efiflash. Personally I would suggest using the modified v0.87 as it is the newest and both DOS and UEFI versions are available thanks to Dsanke. If you want to use a stock version of Efiflash you could try using the force flash switch e.g. efiflash BIOS.BIN /x.
Stock.
You can’t run Efiflash from Windows, Gigabyte has the @BIOS utility for that. As I said above, use the modified version for its ease of use.
efiflash BIOS.BIN
A very good question! I have edit my previous post (I think the issue is using the force flash command) and also revised the Efiflash thread to include FreeDOS as a supported option, thanks for bringing it to my attention. 
No problem at all 
You have prompted me to update the Efiflash thread as I had been a bit lazy keeping it up to date.
Thanks for the very detailed answer @chinobino !! So you would recommend me using the 0.87 mod ones instead of the 1.0? and FreeDOS is okay to use as long as i just do 0.87 mod? i could just run the efiflash.exe on FreeDos without any sufffix, correct?
thanks alot @chinobino now im confident enough to do this. so for any B550 gigabyte before capsule bios, Freedos + 0.87 mod to flash probably fine. i will test this my own, hope my luck, since it doesn’t have any B_Bios B_)
Anyways, the 0.87 mod file on your page cant be reached, maybe fix the link?
help me B360M Aorus Pro 1.0
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Just wanted to say thank you so much I needed this could not have my PC running Blocked your a lifesaver. Do you have a donation link for yourself.
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For the “fptw64 -SAVEMAC -f <DowngradeBIOSName>.bin,” what am I supposed to do? It doesn’t work when I replace DowngradeBIOSName with the name of the bios file (Z390AOPW.F9).
Edit: nevermind, I renamed the file and it worked
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thank you so much chinobino
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What did you rename this too. I am getting invalid syntax errors. I have literally copied the command and renamed my Bios file to many different things, including removing the file extension. I’ve even tried pasting the file path with no success. any idea what I can do?
Read the guide post related to: Flashing Gigabyte while avoiding "Invalid BIOS image" - #313 by Cisco150
Yes, I read it all. I know what I am supposed to do but when I paste the command “fptw64 -SAVEMAC -f .bin,” it wont work. nothing happens. I’ve tried renaming my bios file to exactly “DowngradeBIOSName” even removing the “.f9” extension so that the code is identical and it knows where to pull the file from in my FPT directory. but it still blanks out or gives me an error message in my FPT folder saying that it is wrong.