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I'm trying to patch my bootmgfw.efi file to change the background color of the BitLocker password prompt and other Windows bootup screens. I found the values to search for and replace for the color (B2 67 20 FF) and verified in IDA Pro that they were all near calls to functions related to the display (they were.) I copied the file to my EFI system partition, backing up the original, and rebooted.

When my computer rebooted, after the BIOS finished, it took me to a screen, in my new color, with the following error:

Recovery

Your PC needs to be repaired.

The digital signature for this file couldn't be verified.

Error code: 0xc0000428

You'll need to use the recovery tools on your installation media. If you don't have any
installation media (like a disc or USB device), contact your system administrator or PC
manufacturer.

Press Esc for UEFI Firmware Settings

Pressing Escape didn't take me to a menu where I could disable the signature checking or anything; just my CMOS setup, where I already have Secure Boot disabled.

I was able to easily restore the backup using the installation media as it said, but how can I tell Windows that the invalid digital signature is not the result of malicious software, but rather an intentional change on my part?

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  • Is Secure Boot enabled in the firmware? It may be checking the signature against that.
    – Wes Sayeed
    Apr 22, 2015 at 22:33
  • @WesSayeed I said in the post that it's not.
    – Sparkette
    Apr 23, 2015 at 0:13
  • Oops. Sorry I missed that.
    – Wes Sayeed
    Apr 23, 2015 at 0:28

3 Answers 3

1

Boot into the UEFI (basically BIOS) and disable secureboot. To get into the firmware, search for advanced reboot options and an option should be there. I don't recall the specifics, as when I get a Windows 8 machine I always nuke it and install arch linux, so I only do it once a machine.

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  • As I said, secure boot is already disabled.
    – Sparkette
    Apr 23, 2015 at 19:34
  • Ack, missed that
    – hanetzer
    Apr 24, 2015 at 2:04
0

Press F8 while Windows is starting and choose Disable Digital Signature from the menu. You might have to do that each time though, I'm not sure. If you do, i'd rethink changing the colors. I'd rethink anyway since the signature is there to prevent tampering from viruses and rootkits.

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  • That's for drivers. Besides, this message appears before the point where I can open that menu. Also, it's not just that I want to change the color; I'm mainly just interested in being able to modify the efi programs for fun :p
    – Sparkette
    Apr 23, 2015 at 19:34
  • @flarn2006 Then you're probably out of luck. The point of the certificate check is to prevent tampering with the boot loader, which is what you are doing.
    – Andy
    Apr 24, 2015 at 23:35
  • Yes, but in this case it's not "tampering" because I'm authorized to do it. "Tampering" would be if it's done by malware or someone using my computer without my permission.
    – Sparkette
    Apr 26, 2015 at 0:20
  • @flarn2006 its actually Microsofts code, not yours. The license will tell you for sure. However, you are tampering, which simply means changing, and they explicitly signed it to prevent any changes.
    – Andy
    Apr 26, 2015 at 0:23
  • I thought the word "tampering" necessarily meant it's being done by someone who isn't allowed to do it. Though I don't think what I want to do is what the signature was meant to prevent--generally that's only done for things like DRM where the developers have a reason not to want you to change something. I don't think there's anything like that in the bootloader.
    – Sparkette
    Apr 26, 2015 at 0:42
-1

change your date in bios setup this will help you to boot your system

The digital signature for this file couldn't be verified. bcoz may be your digital signature expired so change your bios date to previous date but every time you need to this until you buy new digital signature.

watch this video to change date in bios. Maybe your system have different bios setup menu

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  • While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes. - From Review
    – Ramhound
    Aug 23, 2016 at 16:03
  • already mention that change date in bios setup please read again. and its worked for me Aug 23, 2016 at 16:23
  • You don't need to comment when reviewers leave, the system generated comment, you should accept or disregard the feedback. I see no written instructions on how to change the date in BIOS setup. A link to a YouTube video isn't an acceptable answer, for many people including myself the video cannot even be watched.
    – Ramhound
    Aug 23, 2016 at 17:23
  • OP appears to have a very specific problem that is fixed by restoring a known good file in place of the one they themselves have modified. If you have reason to believe that this is as simple as a BIOS clock problem then you should state your reasoning for saying so. If you had a similar experience but without modifying files in the way that OP has done then maybe you should consider posting your own question and answer showing what your problem was, how you diagnosed the problem and how you found the fix. As it stands this YouTube link feels a bit like spam.
    – Mokubai
    Aug 24, 2016 at 3:59

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