BIOS / UEFI Boot Option present in BCD?

#1
I wiped an MBR disk, converted it to GPT, pre-created partitions according to MS documentation on UEFI / GPT partition layout defaults (5 partitions - EFI System, MSR, Recovery, Windows + Data partition).

I then installed Windows 10 Home Edition from bootable USB installation media created using the Media Creation Tool on 12/17. This installed Windows 10 Anniversary Update version 1607 right from the start.

System initially booted directly into Windows 10.

On the hidden 'Recovery' partition, I had copied a few WIM files I use for various offline recovery work and utilities. Within the running Windows 10 OS, I un-hid the Recovery and EFI System partitions and assigned drive letters. This was so I could run EasyBCD (v2.3.0.207) and add my WIM files on the 'Recovery' partition to the boot menu. Once this was done I had 3 boot entries:

Windows 10 (default)
Windows 7 Recovery (WinPE Tools)
Windows 10 Recovery (WinRE)

After saving and closing out of EasyBCD, I removed the drive letter assignments and re-hid the 'Recovery' and EFI System' partitions.

After rebooting, the Metro (gui) boot loader menu I got had SIXTEEN other boot entries that all look like the BIOS boot options for different devices and diag utilities:

Entry #1
Name: Setup
BCD ID: {34524b6b-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #2
Name: Boot Menu
BCD ID: {34524b6c-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #3
Name: Diagnostic Splash Screen
BCD ID: {34524b6d-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #4
Name: Lenovo Diagnostics
BCD ID: {34524b6e-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #5
Name: USB HDD
BCD ID: {34524b78-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #6
Name: USB CD
BCD ID: {34524b72-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #7
Name: USB FDD
BCD ID: {34524b73-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #8
Name: ATAPI CD0
BCD ID: {34524b74-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #9
Name: ATAPI CD1
BCD ID: {34524b7a-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #10
Name: ATA HDD0
BCD ID: {34524b75-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #11
Name: ATA HDD1
BCD ID: {34524b76-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #12
Name: ATA HDD2
BCD ID: {34524b77-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #13
Name: ATA HDD3
BCD ID: {34524b7c-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #14
Name: PCI LAN
BCD ID: {34524b79-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #15
Name: Other CD
BCD ID: {34524b7b-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Entry #16
Name: Other HDD
BCD ID: {34524b7d-c6e9-11e6-b8d2-a70e4ae4fd0c}
Device: Unknown
Bootloader Path:

Clipboard Image.png

Any ideas on how these entries just... ~appeared on their own?
 

mqudsi

Mostly Harmless
Staff member
#2
Those are the system EFI options, and are part of the NVRAM for the UEFI. They are hidden in EasyBCD unless Expert Mode is enabled in the options (Tools | Options). However, they should not be showing up in your regular BCD menu.

Can you show/post the EasyBCD detailed mode output?
 
#3
Ah damn, sorry. I used EasyBCD to remove those options from the boot menu - which worked. So I can no longer grab the detailed output. If it happens again (I will be doign similar re-installs over the holiday) I will be sure to grab it. I'm mostly just wondering how they got there.
 

Terry60

Knows where his towel is.
Staff member
#4
Don't go "cleaning up" what apparent junk UEFI leaves around in your BCD, especially if you have "fast boot" enabled.
You might find that you have painted yourself into a corner and can no longer access your PC.
EasyBCD ignores all the dross in overview mode and only displays it in detailed (debug) mode.
 
#5
Well, you are right about THAT!

After going back into EasyBCD after seeing the boot menu - I did indeed remove the extra 16 entries. And as you rightly cautioned against, this has now resulted in my F12 boot menu from the BIOS now missing any options for alternate device. Only 'Windows Boot Manager' remains - and luckily still boots into the OS.

How is EasyBCD able to remove stuff in the BIOS? I thought it only modified the boot config datastore on the 'system' partition?

I was considering using the 'Setup Defaults' from the BIOS to see if that puts back original entries...
 
#6
Setting BIOS defaults returned things to mostly normal - in that I got my BIOS boot menu to select alternate devices back.

However, they're also all back in the boot menu. Detailed/Debug Mode output:

Code:
Windows Boot Manager
--------------------
identifier              {9dea862c-5cdd-4e70-acc1-f32b344d4795}
device                  partition=\Device\HarddiskVolume1
path                    \EFI\Microsoft\Boot\bootmgfw.efi
description             Windows Boot Manager
locale                  en-US
inherit                 {7ea2e1ac-2e61-4728-aaa3-896d9d0a9f0e}
default                 {8aa54c63-2e50-11e3-a87c-d9faf047cf21}
resumeobject            {8aa54c62-2e50-11e3-a87c-d9faf047cf21}
displayorder            {8aa54c63-2e50-11e3-a87c-d9faf047cf21}
                        {3edf2356-c938-11e6-a0a7-3c970e680a6a}
                        {3edf2358-c938-11e6-a0a7-3c970e680a6a}
toolsdisplayorder       {b2721d73-1db4-4c62-bf78-c548a880142d}
timeout                 3

Windows Boot Loader
-------------------
identifier              {8aa54c63-2e50-11e3-a87c-d9faf047cf21}
device                  partition=C:
path                    \Windows\system32\winload.efi
description             Windows 10 Home
locale                  en_US
inherit                 {6efb52bf-1766-41db-a6b3-0ee5eff72bd7}
recoveryenabled         Yes
isolatedcontext         Yes
allowedinmemorysettings 0x15000075
osdevice                partition=C:
systemroot              \Windows
resumeobject            {8aa54c62-2e50-11e3-a87c-d9faf047cf21}
nx                      OptIn
bootmenupolicy          Standard

Windows Boot Loader
-------------------
identifier              {3edf2356-c938-11e6-a0a7-3c970e680a6a}
device                  ramdisk=[\Device\HarddiskVolume3]\Recovery\boot_tools.wim,{3edf2355-c938-11e6-a0a7-3c970e680a6a}
path                    \Windows\System32\Boot\winload.efi
description             Windows 7 Recovery (WinPE Tools)
locale                  en-US
osdevice                ramdisk=[\Device\HarddiskVolume3]\Recovery\boot_tools.wim,{3edf2355-c938-11e6-a0a7-3c970e680a6a}
systemroot              \Windows
detecthal               Yes
winpe                   Yes

Windows Boot Loader
-------------------
identifier              {3edf2358-c938-11e6-a0a7-3c970e680a6a}
device                  ramdisk=[\Device\HarddiskVolume3]\Recovery\WindowsRE\Winre.wim,{3edf2357-c938-11e6-a0a7-3c970e680a6a}
path                    \Windows\System32\Boot\winload.efi
description             Windows 10 Recovery (WinRE)
locale                  en-US
osdevice                ramdisk=[\Device\HarddiskVolume3]\Recovery\WindowsRE\Winre.wim,{3edf2357-c938-11e6-a0a7-3c970e680a6a}
systemroot              \Windows
detecthal               Yes
winpe                   Yes
 
#7
But then, here is the Overview output:

Code:
There are a total of 19 entries listed in the bootloader.

Default: Windows 10 Home
Timeout: 3 seconds
EasyBCD Boot Device: C:\

Entry #1
Name: Setup
BCD ID: {31f5933e-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #2
Name: Boot Menu
BCD ID: {31f5933f-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #3
Name: Diagnostic Splash Screen
BCD ID: {31f59340-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #4
Name: Lenovo Diagnostics
BCD ID: {31f59341-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #5
Name: USB CD
BCD ID: {31f59342-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #6
Name: USB FDD
BCD ID: {31f59343-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #7
Name: USB HDD
BCD ID: {31f59348-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #8
Name: ATAPI CD0
BCD ID: {31f59344-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #9
Name: ATA HDD0
BCD ID: {31f59345-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #10
Name: ATA HDD1
BCD ID: {31f59346-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #11
Name: ATA HDD2
BCD ID: {31f59347-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #12
Name: ATA HDD3
BCD ID: {31f5934c-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #13
Name: PCI LAN
BCD ID: {31f59349-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #14
Name: ATAPI CD1
BCD ID: {31f5934a-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #15
Name: Other CD
BCD ID: {31f5934b-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #16
Name: Other HDD
BCD ID: {31f5934d-c936-11e6-a0a7-806e6f6e6963}
Device: Unknown
Bootloader Path: 

Entry #17
Name: Windows 10 Home
BCD ID: {current}
Drive: C:\
Bootloader Path: \Windows\system32\winload.efi

Entry #18
Name: Windows 7 Recovery (WinPE Tools)
BCD ID: {3edf2356-c938-11e6-a0a7-3c970e680a6a}
Device: [\Device\HarddiskVolume3]\Recovery\boot_tools.wim
Bootloader Path: \Windows\System32\Boot\winload.efi

Entry #19
Name: Windows 10 Recovery (WinRE)
BCD ID: {3edf2358-c938-11e6-a0a7-3c970e680a6a}
Device: [\Device\HarddiskVolume3]\Recovery\WindowsRE\Winre.wim
Bootloader Path: \Windows\System32\Boot\winload.efi
 

mqudsi

Mostly Harmless
Staff member
#8
A pro-tip not many know: the first time you run EasyBCD, it makes a backup of your BCD automatically and saves it to the My Documents folder. It can be restored even when booted into the Windows recovery CD.
 

Terry60

Knows where his towel is.
Staff member
#9
Are you using the latest version os EasyBCD (2.3) ?
My overview mode looks like a simple two OS choice contrasted with the many other options in detailed mode.
 
#10
@mqudsi: thanks, and yeah I've seen those backups. But I'm still trying to understand how changes I made in EasyBCD wiped boot DEVICE options from the EFI BIOS?

These are my first attempts at working on a system with EFI, so apologies if some of this is known territory, but new for me. This is a Lenovo T530 that came with Win7 installed and the BIOS set to Legacy boot mode and MBR disk partitions. After upgrading to Win10, I've changed my BIOS over to UEFI boot mode and manually created the MS recommended GPT partitions, and re-installed Win10 as mentioned. But I've never seen BIOS level boot options appear in a Windows boot manager boot menu... though I have seen OEM diag utilities referenced when looking at raw BCD output from bcdedit.exe in the past, and I've always just ignored them since they never appeared in the boot menu and assumed there were flags of some sort that affected their visibility.

Is there some relationship between the boot DEVICE options in the BIOS and disk files on the EFI System partition?

Before I 'cleaned' out all of these entries - I believe the 'Detailed/Debug Mode' output properly reflected all the additional BIOS boot options like you would expect, but which is not the case now after resetting the BIOS. That said, I should also tell you that the actual boot menu doesn't show any of those extra options like it did before I deleted them in EasyBCD the first time. So, it's really weird:

- they're NOT displayed in the boot menu
- they do NOT show up in debug mode output
- they DO show up in the overview output (and BIOS again)?

To be clear, I don't really care about having most of them... the ONLY thing I wanted was to regain control over being able to use the F12 BIOS boot menu to select a temporary boot device (usually a USB drive), which is now resolved since I reset the BIOS. However, I started out with a completely clean re-installed system and would like to understand what happened. I can wipe the disk, re-install new partitions and experiment if anyone is inclined to help explain things... don't always have the luxury of doing that - but I've backed up all the data from this laptop and will happily screw with it to learn 'now' before messing with other ppls UEFI based PC's :smile:...

@Terry60: yeah - that is wh yI posted. It's weird...

As far as version, I mentioned v2.3.0.207 in first post. I "think" that is latest released version.
 
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