Moving / recreating EFI partition

I know this thread is a little old, but I created an account and just wanted to say Thank You, Kyhi!

Fixed me right up. For anyone wondering, I did this with Windows booted to the desktop, and it worked just fine. In my case, I had the EFI System Partition on the HDD instead of my SSD, which is apparently an issue when you install Windows 10 with both drives connected.

Kyhi said:

- Boot the computer using the Windows 7/8/8.1/10 installation media.
- On the first screen, press SHIFT+F10 to bring up the command prompt.
- Run the following commands at the command prompt.

diskpart
list disk
select disk # Note: Select the disk where you want to add the EFI System partition.
list partition
select partition # Note: Select the Windows OS partition (# number) or your data partition.
shrink desired=100
create partition efi size=100
format quick fs=fat32
assign letter=s
list partition
list volume Note: Note the volume letter where the Windows OS is installed.
exit

bcdboot X:\windows /s S:
Note: Replace "X" with the volume letter of the Windows OS partition.

BCDBoot copies the boot files from the Windows partition to the EFI System partition and creates the BCD store in the same partition.

Remove the Windows installation media and restart the computer into your BIOS settings and set the SSD as the First Boot Device.

You need to set the new EFI System Partition's ID in diskpart or you won't be able to update windows (even though it will boot)!

set id=c12a7328-f81f-11d2-ba4b-00a0c93ec93b

Thank you for this guide!
I tried a bunch of different methods online however none worked for me until i found this.

I installed windows to an SSD while a data HDD was plugged in. The EFI partition for some reason got put on the data hdd.

bcdboot X:\windows /s S:
Note: Replace "X" with the volume letter of the Windows OS partition.

For me C was my ssd while G was my HDD. I used "bcdboot C:\windows /s S:"
Thanks kyhi!

Kyhi said:

bcdboot X:\windows /s S:
Note: Replace "X" with the volume letter of the Windows OS partition.

I tried this and I just keep getting the failure method
I tried C:\windows /s S: (c is the nvme with the os)
I tried D:\windows /s S: (d is the hdd with the efi)
I tried assigning a letter to the original efi and running X:\windows /s S:

What am I doing wrong and how do I fix it?

DaQauckers said:

I tried this and I just keep getting the failure method
I tried C:\windows /s S: (c is the nvme with the os)
I tried D:\windows /s S: (d is the hdd with the efi)
I tried assigning a letter to the original efi and running X:\windows /s S:

What am I doing wrong and how do I fix it?

Need to see a screenshot of disk management...
Disk Management - How to Post a Screenshot of | Tutorials

NavyLCDR said:

Need to see a screenshot of disk management...
Disk Management - How to Post a Screenshot of | Tutorials

It's fine, I got it working in the end.

I was trying to do it from inside windows, as a previous comment had suggested was possible.
Apparently there was some weird drive remapping happening in windows that was preventing it.
Ran from the creation media and found that the drive letters I saw in windows weren't even actually assigned and the letters for all other volumes were different than they had been reported previously.

It's all working now. Huge thanks to this thread for helping me actual start booting of my nvme

pflau said:

So this is the top google search result for "moving efi system partition". Well let me just add this one thing: bcdboot X:\windows /s S: is not enough. You also need to manually copy all the files in your original EFI partition to the new EFI partition you just created. That is, assign a letter to the original EFI partition, and do an xcopy /s t:*.* s: where t: is the letter you assigned to the original EFI partition. Without those files your BIOS would not recognize it as a bootable EFI partition. You're welcome.

I just want to point out that for me, this was the only thing that worked. My original drive was a samsung SSD - the new one was a Samsung m2. The original samsung SSD contained the only functioning EFI. I Tried all the different permutations outlined in this thread and just ended up with a bunch of pointless 100mb partitions that really cluttered up my potential boot sources. Once I applied the copy tactic to one of the handful of efi partitions that'd been created in my stumbling around diskpart, a functioning one was created.

That wasn't the end, of course...Had to manually go into bios and disable all these boot drives until I found out which one(s) worked since there were so many non-working ones with practically the same name. Lets just say I won't be screwing around with boot stuff for a long while again. Every time I do it's hours down the toilet. Dual booting linux, shudder at the memories....The whole point of this was to try and do the intel optane business but I think I'm just going to stick with what I have for now....

Kyhi said:

- Boot the computer using the Windows 7/8/8.1/10 installation media.
- On the first screen, press SHIFT+F10 to bring up the command prompt.
- Run the following commands at the command prompt.

diskpart
list disk
select disk # Note: Select the disk where you want to add the EFI System partition.
list partition
select partition # Note: Select the Windows OS partition (# number) or your data partition.
shrink desired=100
create partition efi size=100
format quick fs=fat32
assign letter=s
list partition
list volume Note: Note the volume letter where the Windows OS is installed.
exit

bcdboot X:\windows /s S:
Note: Replace "X" with the volume letter of the Windows OS partition.

BCDBoot copies the boot files from the Windows partition to the EFI System partition and creates the BCD store in the same partition.

Remove the Windows installation media and restart the computer into your BIOS settings and set the SSD as the First Boot Device.

I'm having the same issue right now. Just wondering if this will remove all my current data on the SSD?

- - - Updated - - -

cereberus said:

Why not just copy the EFI from old drive to new drive using minitool partition wizard free - done it zillions of times.

is there any guide or video tutorial you might have? I would like to try this instead of the cmd thing