AsRock Z87 extreme4 modded bios - Security check failed.

Hi all,
I have AsRock Z87 extreme4, and cannot flash modded bios. It says "Security check failed". How can I over come this problem.
Thanks in advanced.

@ saglamtimur:
Welcome at Win-RAID Forum!

What have you modded and how did you try to flash the modded BIOS?


I have modded it BIOS version 2.30 with using your guide "Easy AMI UEFI BIOS Modding:Use of the "UEFI BIOS Updater" (UBU)", and I used "Instant Flash"

Which modules did you update?
Did you update the CPU Microcode as well?

All of them, CPU Microcode as well. Shouldn’t I ?

I got it. I use afudos. First tried to flash with it but it said can’t flash because of file size mismatch. Interesting, it was same before and after (8196 Kb). Anyway, I backed up the bios (which is latest genuine one) with afudos. More interesting it is 6144 Kb. And then I modded it, and flashed with afudos with success. Seems everything works fine and installed Win 8.1 without any problems.

The simple reason for my question was to facilitate the search for the reason why the BIOS flashing procedure failed. According to SoniX, the developer of the UBU Tool, the CPU Microcode update should be not very problematic with ASRock mainboards.
I hope, that SoniX or someone else can help you to solve the problem.


Thanks for your updated information.
It is fine, that you succeeded at least!

Thanks for your interest Fernando. As I mentioned previous post, I somehow able to flash it. Any clue why backed-up bios with afudos and genuine one’s file size different?

You have to edit the BIOS file with HxD, highlight from offset 0000000 to 00001000, and delete it. Then click save.

vendor supplied image is multipart and included with (signed cap header for security, me firmware and bios firmware,etc) but afudos doesn’t care other parts of firmware it will only backup with bios region(firmware) that’s why there is no security verification and backup is pure bios(uefi) image

off topic question
are you turkish because your nickname is a turkish name

Thanks for the info.


If I remember correctly (I did lots of of test), I did it already but failed. But will try again. Thanks for that.


me too :slight_smile: //Merhaba

If I remember correctly (I did lots of of test), I did it already but failed. But will try again. Thanks for that.

correct way to edit bios image is tricky different offset used each model all you have to compare both of backup and original rom

but the best is to use the backup does not distress