ASUS Z170 Flash Back to Older BIOS How To

Credits for this guide go to elmor. Thanks for your work!

WARNING: This may cause your system not to start. Use at your own risk.

The procedure below allows you to flash an older BIOS on motherboards without USB BIOS Flashback feature. The lack of this feature means there’s no simple way to recover if things go wrong.

This will help to solve the error “selected file is not a proper BIOS”.

If you want to use non-K OC with recent ASUS boards, you often can’t flash back to an older BIOS the normal way. So you have to follow this guide to downgrade the BIOS.


First download the required tools here:

UEFITool v0.21.5
2.67 MB | 4895 downloads
Flash Programming Tool
2.79 MB | 25894 downloads


Prepare the BIOS file for use with FPT

  1. Get the BIOS for your motherboard in CAP format (in this case MAXIMUS-VIII-IMPACT-ASUS-0019.CAP)
  2. Open the CAP file in UEFITool




Extract body



Using Flash Programming Tool to flash the BIOS on your system

  1. Open a command prompt with Administrator rights and navigate to your FPT directory (Note: There are DOS/EFI/Win32/Win64 versions, this guide uses the Win64 version.)
  2. Flash the BIOS by using the command fpt -bios -f BIOS_FILE.ROM



The BIOS is now flashed to the old version and you can do non-K OC :)

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  • Raven

    Worked great thanks.

  • Mal

    Doesn’t work for me. After I hit enter in the command prompt, it gives me the error “fparts.txt not found” even though its right next to it. Does anyone have a fix?

  • bur1

    thank you out. and for the first time I went to a service to install. I did not know that so easily

  • Raven


    So I flashed my Asus z170i and did as said in the guide and my 6500T will not go above its max core speed of 2.8Ghz, any suggestions? thanks.

  • Raven

    Sorted it, disable turbo mode in cpu power.

  • jeff1101

    Hi der8auer,

    I understand the instructions but how do I get the older version of my BIOS in CAP format?

    • jeff1101

      Finally got the nerve to try it and it works! Flashed from 1809 back to 9006. It was nerve wracking since the flash itself took a looonnnnggg time to complete. At one point I thought it froze or was stuck in an endless loop. The ‘erasing flash block’ message kept repeating for seems like forever.

      It was so scary I dont think I want to try that again so Im sticking with 9006 for a while. For all the others who want to try it please make sure you know what your doing and remember the flash instructions and follow it to a tee. Thanks.

  • Mick

    Hi when I type fpt etc it comes up as access denied on asus z170I pro gaming itx

  • Nik D

    Works fine with me, thanks a lot!
    The point is to save cmd.exe and *.rom file EXACTLY in WINDOWS64 subfolder under the Flash Programming Tool directory

    • daniel

      whatcmd.exe file are talking about Nik D? I get that youre supposed to save the .rom fie in the windows64 folder, but I don’t know what I’m doing wrong. I get the error saying it is not an external or internal command.

  • Schiffneru

    Hi, what to do?
    Error 368: failed to disable write protection for the bios space
    FPT Operation Failed.
    Asus z170-A, flash prog tool – bios 3007

  • Jonas

    A Video showing the steps would be great


    Is there also such a flashback method for gigabyte z170 boards ?

  • kevin

    Someone is there to answer ??

    we all have this error: Error 368: failed to disable write protection for the bios space
    FPT Operation Failed.

    I have tried in the bios after this solution but still not able to downgrade to this bios i get this error:

    Error 368: failed to disable write protection for the bios space
    FPT Operation Failed.

  • creolecaf

    Hi guys ! Please dont use these tools to flash from last 2002 official bios to 8002 overclock bios : It will beak your board just as I broke mine. Don’t know what happened but the tool did its job with no bugg or warnings. It ended normally the flash process but the fact is my board will not boot again. I just wanted to advise…

  • Tobias

    Well, im not getting very far at all with this.

    After entering the command all i get is the following:

    Error 368: failed to disable write protection for the bios space
    FPT Operation Failed.

    I have no idea how to solve this, help?

  • RustyRoj

    Has anyone spoken to Asus about this yet? I’ve emailed support but so far nothing.

    • RustyRoj

      Well Asus emailed me back. Confirmation we can’t flashback out Z170-AR boards despite the box, manual, website. RMA hell it is then.

      “Hello Roger,

      Good Day!

      Thank you for your reply!

      Thank you for bringing your issue to our attention. I am very sorry for any inconvenience that this issue may have caused

      For your query, we are sorry but you cannot downgrade BIOS on your motherboard Z170-AR.  Thank you for your understanding

      In this case, it seems that you try all troubleshooting you can. We are so sorry but we need to do some tests directly on your product to find out the root cause. As per checking, your product is still in-warranty. Therefore, we highly recommend that you please contact your retailer for further test and RMA (Return Material Authorization) service.

      Thank you for your cooperation and sorry for this inconvenience that caused”

  • Ben

    Error 368: Failed to disable write protection for the BIOS space.
    FPT Operation Failed.
    How can i fix this?

  • Rob

    Actually I have the latest bios (3016) from asus-website for Z170 Pro Gaming .
    When I’m trying to downgrade to non-k-OC-bios 1301 from here, there is “error 368 failed to disable write protection for the bios space”, too :-(
    How can I fix it?

  • fptw64.exe -bios -f file name

  • Harry Trent

    I think this would have worked but I got this message: Error 368: Failed to disable write protection for the BIOS space.
    FPT Operation Failed. I wish you had mentioned this potential problem. I’m not sure there is a convenient workaround but just to mention you might encounter this would have been helpful.

  • Frank

    I am having the same issue… Wish I had found that thread before upgrading. My issue is that my VD-T no longer works, hence: I cannot boot my VMs. Oups.

    Will contact asus, but likely: I need a replacement/repair…

  • herc

    anyone tried on asus z170-A with 3007 bios?
    downgraded to 0050 ?

  • RRR

    downgraded from bios 1803 to 603 for Asus z170-k without any problem. Thanks!

  • RRR

    oops, I meant 602 :)

  • Joe

    3*** bios has completely blocked downgrading so if you are on it and want non k oc you will need a new bios chip with older bios flashed. Unless some smart guy finds a work around.

    • soren forssell

      On my z170-e with 3007 bios I could not flash back to 0050. Went to E-bay and bought a bios chip with 1203 bios on it for £12. No problems flashing back to 0050 after that.

  • Mairou

    I tried to do this before any good guide and it failed, making my PC unusable for 3 weeks (until I got my replacement BIOS chip). Well, I’m dumb enough to do it again if it gives me any benefit and it worked perfectly!!! Also a good point to make in the guide would be to flash older version of the OFFICIAL bios, because it’s not quite clear.

  • Ahmetül

    Error 368: Failed to disable write protection for the BIOS space.
    FPT Operation Failed.
    How can i fix this? ? Help mee please

  • NgL

    My z170i is now on 3016. This method won’t help me downgrade it back to 9006. I would like to know if there another way or can a bios chip with 9006 can still help me overclock my 6400?

  • paul

    Okay , I have version 1904 version of the bios on my board , if I downgrade to suitable bios for a i5 6400 for overclocking , do I still have the option to flash with the latest bios at a later date , if I sell my board etc or decide to upgrade my chip for a K version ?

  • dreamerd

    appreciate the work but the guide is very vague and confusing, cant come close to getting it right cant you help us all out??

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