Can't get UEFI drive to boot - help

I would:

Code:

format S: /q /fs:FAT32
bcdboot C:\Windows /s S: /f UEFI

Navy - I executed your 2 lines and I still get an error when I am prompted to select a boot drive and I select the EFI option. Were there other assumptions about my BCD store entries you made?

thornev said:

Navy - I executed your 2 lines and I still get an error when I am prompted to select a boot drive and I select the EFI option. Were there other assumptions about my BCD store entries you made?

What is the make and model # of the external USB enclosure you are using?

Navy - That info was posted several posts before. But I'm no longer using the USB port. I've got the new NVMe inside the PC in an M.2 slot.

You could try disconnecting all the other drives. It's possible the motherboard is trying to boot from one of the other drives, especially if there is an EFI boot folder structure on any of them.

Yes, Navy, that has been a suggestion earlier. The only 2 boot drives I have now are the 2 NVMe drives and I can't take out either one. Well I could for testing purposes but then I have to have both of them in at least before I'm ready to stop using the older NVMe. OK, something to try. THanks. G'night.

Hi folks
there's "fuddery" around this whole issue. GPT is not mandatory for booting EFI, however gpt is required for Ms file systems if your HDD > 2TB or so and also required if you want more than 4 primary partitions.

Cheers
jimbo

steve108 said:

@thornev,
Another possibly useful video for you: How To Boot Windows 10 From An External SSD Or Hard Drive Quick And Easy - YouTube

Note that he installed 21H1

Note 2: The free version only supports Windows Home: [Official] Best Free Windows To Go Creator Wizard Helps Create Portable Windows 11/10/8/7! (click comparison tab)

Hi there

@thornev

easy to create "Windows to go" type systems on external USB devices -- absolutely no need for Windows to Go creator or any other 3rd party software -- can be done easily using a Windows install disk booted into command mode / winpe type of system and just using native windows commands.

I've made several posts on this on W11 Forums --use physical "Virtual Hard disk" files (not VM's) and you don't need to have HYPER-V enabled either.

Here totally running from a USB -- have several Windows systems and a Linux system :





Here's how to do it : including adding a Linux system (omit that part if not wanted)


So procedure is this :

1) prep main Disk - boot a winpe type system - macrium Free with the command box is an eay way to start plus ensure your install media is mounted say on vol D: -- Can be either internal HDD or external USB disk --external SSD via SATA->USB 3connector is just fine and response time will be excellent too.

2) disk part, clean, convert gpt.
3) create partition efi size=100 (If installing loads of Windows OS'es and linuxes then make a bit bigger e.g 300mb)
4) format quick fs=fat32, label="System"
5) assign Letter=H (or any you want)
6) create partition primary msr size=128 (leave unformatted)
7)) create partition primary
8) format quick fs=ntfs label="Main"
9)assign label=M
10) list vol Check the letters etc are OK
11) select vol xxx (should be the "M" partition
12) Create vdisk file=M:\Windows.vhdx maximum=60000 type=fixed (change 60000 to your wanted size) - probably will take a minute or 2 - you'll see progress status.
13) select vdisk file=M:\Windows.vhdx
14) attach vdisk
15) list vol -- the Vdisk will probably be shown without a letter
16) select vol xxxx -- select the vdisk
17) assign letter = V
18) exit

Now apply the windows image from your windows install media say on D:

so still in command mode
dism /Apply-Image /ImageFile:\sources\install.wim Index:1 /ApplyDir:V:\ --- change index if windows edition you want is not nr 1. This step takes a little while depending on hardware -- progress is indicated.

now the boot manager :

v:
cd V:\windows\system32
bcdboot v:\windows /s H: /f UEFI

reboot and remove external devices.

If this is the only OS then this will be the default and boot automatically.

If you want another Windows do the same again booting from a winpe type media (e.g winpe itself / macrium free stand alone etc). Winpe itself or anything with a base winpe in it like Macrium free or even a Windows recovery media disk will work.

Don't add the 2nd OS boot mgr entry (bcdboot) from within a running Windows if you are running from a "Virtual hard drive" and only have Virtual Hard drives -- - it can hose up the primary boot manager -- at least I've found that's the case. By all means create the "Vhdx" and apply the image from within windows but boot the winpe type of system to attach the vdisk and create the bcdboot entry as shown.

Now the Linux system :

Add one partition for the root / partition (primary)
Add another partition for /home
Another for swap (optional)

Format those partitions as linux partitions from your linux install media -- I find xfs is the best but any Linux fs will do
install grub to your existing UEFI partition according to your Linux system -

Install your Linux system from the install media to the / and /home partitions

ensure :

1) ntfs-3g installed so you have read / write to Windows NTFS files
2) efibootmgr installed
3) ensure the original efi 100mb partition is big enough that will probably be OK but I'd make it 300mb just to be sure if loads of Windows systems and other OS'es on it. YOU DON'T NEED TO CREATE ANY MORE EFI PARTITIONS ON THIS HDD. !!!!

In the grub install mount the EFI partition -- mkdir /mnt/boot and then mount /dev/sdx1 /mnt/boot so you can install grub to the efi partition and then create the grub.cfg file -- I'll leave details there as different Linux distros have various ways of loading / configuring grub. I'm running arch-linux but fedora works as does Linux mint. Haven't tried others BTW.

for arch linux boot manager is done : (assuming you've installed the base system and still in arch-chroot /mnt)
pacman -S grub efibootmgr (package manager install efibootmgr and grub)
mkdir /mnt/boot/efi
mount /mnt/boot/efi /dev/sdx1 --- the HDD's EFI partition
grub-install --target=x86_64-efi --bootloader-id=GRUB --efi-directory=/boot/efi
grub-mkconfig -o /boot/grub/grub.cfg

Cheers

jimbo

jimbo - Instead of installing a fresh Windows from winpe, can you alter your instructions so that I can clone my existing Windows 10 partition? The reason is so that I can keep all my apps and their data. If I don't do that then I have to reinstall all my apps and somehow migrate their data. Thanks, I appreciate the time you took to write that up for me. Thorne

- - - Updated - - -

Here's a question.... It seems to me that the BCD stores for legacy and EFI are not always built correctly. Specifically they seem to point to incorrect OS volumes. Maybe it's my understanding of the BCD store content that is incorrect. I've used "bootrec /rebuildbcd" a few times. How reliable is that command to build correct BCD store entries? Do you folks regularly edit BCD store entries to ensure they are correct? I do backup my BCD stores before editing them, but I've never restored any of them because the reason I'm editing them is that they don't boot my EFI drive (well, that is the EFI BCD doesn't boot its OS).

I've been editing the BCD stores regularly and I'm wondering if perhaps I am the one who is causing additional issues because of my misunderstanding of BCD entries. I've done a lot of research on BCD stores so I don't think my knowledge is that far off. I'd like to hear what you all do, if anything, to "customize" or "correct" your boot drive BCD entries.

That's why I suggested formatting the EFI system partition and recreating the BCD with the bcdboot command. I think your problem is that your computer is booting from a BCD that is located somewhere other than the EFI system partition you think it is booting from.