UEFI remove unwanted boot entries from BIOS solved easily

CountMike said:

I know that but bootstrap has to load at least part of OS kernel to even show BOOT menu. UEFI BIOS itself is not changed at all, It has own boot order list for physical drives.
BOOT order shows all bootable devices which in UEFI mode shows as something like this
"Windows UEFI BOOT on such and such disk"
I can show you a picture of it in my BIOS.

Hi there
that's not quite true exactly -- as "Which OS" are you talking about

For example at Boot time my HP proliant Gen 10 microserver has a Press F11 key to prompt for boot menu -- so no Windows or any other OS other than the BIOS program is active at that point -- so there's always a "miniscule" OS even if it's only one or two instructions long and loads the rest from a ROM / EPROM.

No Windows / Linux etc is active at the boot menu prompt on that particular server -- just the HDD's / NIC devices it (the BIOS program) finds with a "bootable" component.

From Windows with BCD the boot menu may then offer other boot possibilities - but that's AFTER the Windows OS has been loaded FROM an HDD/SSD and is doing its initialisation bit.

Cheers
jimbo

jimbo45 said:

Hi there

@dictum
@logictonic1

Another way
Boot up any UEFI Live Linux distro and then ensure you have efibootmgr installed on it. (Or those that have dual boot with Linux -- boot into that - also ensure efibootmgr is installed).

now run the efibootmgr command and you'll see a list of boot entries for example in my case :


Attachment 262077


delete the HEX number(s) of the boot entries you want to delete

Job done --even easier !!!!!

Cheers
jimbo

What is the command to delete?
I got like this:

Code:

sudo efibootmgr 
[sudo] password for shmuel: 
BootCurrent: 0008
Timeout: 1 seconds
BootOrder: 0008,0009,0006,000A,0000,0005
Boot0000* Windows Boot Manager
Boot0005* MX19.1
Boot0006* MX19
Boot0008* ubuntu
Boot0009* manjaro
Boot000A* Hard Drive
shmuel@shmuel-Kubuntu:~$ delete Boot0009
delete: command not found

Hi there
@shmu26

as root or sudo :

efibootmgr -b hexnr of boot -B

e.g to delete manjaro boot in your case

sudo efibootmgr -b 0009 -B

Cheers
jimbo

jimbo45 said:

Hi there
@shmu26

as root or sudo :

efibootmgr -b hexnr of boot -B

e.g to delete manjaro boot in your case

sudo efibootmgr -b 0009 -B

Cheers
jimbo

Perfect, thanks

jimbo45 said:

Hi folks
with UEFI if you've installed say some Linux versions and you don't want them any more you might still see these at boot if you go into your BIOS boot menu.

Easy way to fix these i.e remove them

1) Go into command mode (run as administrator)
2) type bcdedit /enum firmware (space between enum and firmware

3)Now you'll see a list

4) To delete entries you don't want
type bcdedit delete identifier where the identifier is shown in your list. Include the sigiddly braces { }

Easy -- job done

If you are worried about this just simply backup the EFI partition with Macrium - you don't need to back up the rest of the system. If boot fails because you deleted wrong entry simply restore the EFI partition (it's only 100MB or so - takes seconds with macrium and works -- I deliberately hosed up an entry to test this --restored partition and system booted fine).

Cheers
jimbo

Hey jimbo, sorry for the direct reply, but I can't seem to get help with this problem anywhere else. Anyways, I added a RAID 1 boot entry to my BIOS using the Phoenix Technologies UEFI Shell following the instructions posted here:

L702x Modded GPU BIOS | Page 60 | NotebookReview

Now I want to delete this entry as I no longer use RAID 1, but I can't seem to do it using any of the methods stated here. Whenever I try to locate the boot entry either using the Windows Command Prompt or even your Linux trick, it doesn't show up. I can see it in the Boot menu of the BIOS, and I can see it output from the UEFI Shell, but it's invisible to everything else. Just out of curiosity, do you know how to delete entries using that UEFI Shell?

Huge thank you for any and all help!

Crazy Gaston said:

Hey jimbo, sorry for the direct reply, but I can't seem to get help with this problem anywhere else. Anyways, I added a RAID 1 boot entry to my BIOS using the Phoenix Technologies UEFI Shell following the instructions posted here:

L702x Modded GPU BIOS | Page 60 | NotebookReview

Now I want to delete this entry as I no longer use RAID 1, but I can't seem to do it using any of the methods stated here. Whenever I try to locate the boot entry either using the Windows Command Prompt or even your Linux trick, it doesn't show up. I can see it in the Boot menu of the BIOS, and I can see it output from the UEFI Shell, but it's invisible to everything else. Just out of curiosity, do you know how to delete entries using that UEFI Shell?

Huge thank you for any and all help!

@Crazy Gaston

Hi there
I think the easiest way is to simply boot up any Linux live distro from a USB disk - ensure efibootmgr is installed (for example if you install say live fedora linux type sudo dnf install efibootmgr)

now type sudo efibootmgr

you should see something like this

BootCurrent: 0002
Timeout: 1 seconds
BootOrder: 0000,0002,0003,0001
Boot0000* Windows Boot Manager
Boot0001* Hard Drive
Boot0002* ubuntu
Boot0003* ubuntu

to delete entries you don't want type :

sudo efibootmgr -b <bootnum> -B where <bootnum> is the hex num of the entry to delete.

If it's not a boot entry then you'll have to browse the /efi partition on the HDD itself and delete the entry manually

If you get 100% stuck on this then just back up the OS'es you want (Free Macrium works a treat for imaging the OS - Windows --for Linux it's a bit trickier - you can image the OS but on restore you'll probably need to fiddle around with /etc/fstab to ensure consistency of partition GUIDS) - usually it's simple just to re-install the linux OS again) then simply from command prompt (can do it from Macrium stand alone recovey disk --there's a Command prompt icon at bottom left of screen) use the diskpart command and clean the relevant HDD and re-partition.

Cheers
jimbo

jimbo45 said:

@Crazy Gaston

Hi there
I think the easiest way is to simply boot up any Linux live distro from a USB disk - ensure efibootmgr is installed (for example if you install say live fedora linux type sudo dnf install efibootmgr)

now type sudo efibootmgr

you should see something like this

BootCurrent: 0002
Timeout: 1 seconds
BootOrder: 0000,0002,0003,0001
Boot0000* Windows Boot Manager
Boot0001* Hard Drive
Boot0002* ubuntu
Boot0003* ubuntu

to delete entries you don't want type :

sudo efibootmgr -b <bootnum> -B where <bootnum> is the hex num of the entry to delete.

If it's not a boot entry then you'll have to browse the /efi partition on the HDD itself and delete the entry manually

If you get 100% stuck on this then just back up the OS'es you want (Free Macrium works a treat for imaging the OS - Windows --for Linux it's a bit trickier - you can image the OS but on restore you'll probably need to fiddle around with /etc/fstab to ensure consistency of partition GUIDS) - usually it's simple just to re-install the linux OS again) then simply from command prompt (can do it from Macrium stand alone recovey disk --there's a Command prompt icon at bottom left of screen) use the diskpart command and clean the relevant HDD and re-partition.

Cheers
jimbo

Ok, so I did a little more research on this, and figured out why I can't see the entries. So when I try to use the Linux efibootmgr, again, all of the boot entries are invisible. The only one that is displayed is Boot000* Windows Boot Manager, and I found out why. L702x PCs can't boot in UEFI Mode, only Legacy mode. That's why I have to use UEFI Shell to create the entry in the first place.

With that being said, do you know what commands would delete the entry through UEFI shell? Or do you know of another work around? Thank you for your help.

jimbo45 said:

@Crazy Gaston

Hi there
I think the easiest way is to simply boot up any Linux live distro from a USB disk - ensure efibootmgr is installed (for example if you install say live fedora linux type sudo dnf install efibootmgr)........

Cheers
jimbo

So just out of curiosity, do you have any other advice? Do you know how to make the boot entries visible from a Legacy boot? Again, any help would be appreciated.

Crazy Gaston said:

So just out of curiosity, do you have any other advice? Do you know how to make the boot entries visible from a Legacy boot? Again, any help would be appreciated.

Hi there

EFI boot is usually a file on an actual device which is readable and editable -- I think for MBR you will need to dump the first block from the device and also the BIOS MBR is actually a tiny program in one of the MOBO's chips -- a EPROM or whatever -- no idea at all how to read those but I'm sure there will be some here who can find ways of doing it.

UEFI is actually easier to manage than the old MBR IMO !!!

On linux systems all the files are usually on directory /efi/boot or /boot/efi with partition flags set to esp,boot

Cheers
jimbo