How to enlarge Windows 10 EFI partition

My system currently has this partition setup:

I would like to enlarge /dev/sdb2, the EFI System Partition, to 500MB.

The problem is that I do not want to delete the Windows Recovery Partition (/dev/sdb1) and I do not know how to move the unallocated space after /dev/sdb4 to be adjacent to /dev/sdb2.

Using Linux, I can move the /dev/sdb4 partition to the right by 400MB, but then I cannot move the MSR (/dev/sdb3) as it is of unknown format.

Using Windows, I cannot move the Windows10 partition, and by the way the MSR partition seems hidden so I cannot act on it.

So I'm stuck with only 100MB of EFI partition which is totally insufficient for multiple kernels.

AF7

Posted 2016-07-28T13:10:32.597

Reputation: 161

Backup. 2. What about to create a partition at the end of /sdb5 and use directly that one? You can always re-format the unknown partition when you are sure that it is not in use... 3. Backup. 4. Backup...

< – Hastur – 2016-07-30T21:23:16.360

@Hastur the unknown partition is Microsoft's MSR and I'd like it to stay untouched. I don't use Windows much but I do not want to mess it up. So you are basically suggesting to move the EFI partition to the 400MB space I previously created? Will this mess with the BIOS (some data of which is also contained in the EFI) or Windows? Do I have to edit some Windows config for this? As for Linux, I know it's not a problem. – AF7 – 2016-08-01T06:48:13.680

I meant inside /sdb5... (faster) from the end if it is allowed... – Hastur – 2016-08-01T07:39:47.490

@Hastur Sorry, I do not understand. Could you please elaborate? – AF7 – 2016-08-01T09:33:26.647

Sorry elaboration idea. About grub. From mobile (+holyday) I cannot more :)

– Hastur – 2016-08-01T10:25:29.893

Answers

To move sensitive partitions, you need to boot from CD or USB.

Some free partition editors that have boot CD are :

Of the two, MiniTool has the better user interface.

I suggest before starting, to take an image of the entire hard disk on external media, using a product that also has a rescue boot CD. Create this rescue CD and test whether it can see the backup disk and image, just in case, as any mistake can destroy the disk and render the installed operating systems unbootable. My favorite backup product is the free AOMEI Backupper.

Below is the procedure to follow once you boot into the partition editor's boot CD. It brings the unallocated space to below the EFI (sdb2), but as unallocated space is not counted as a partition, one needs to rather move its adjoining partition.

Move sdb4 right/down by 400MB
Do the same for sdb3 (MSR). The unallocated space should now directly follow sdb2.
Reboot to test if the disk still functions. If reboot is impossible, then the MSR could not be moved - see below.
Resize sdb2 to include the unallocated space
Reboot

If the tools fail to move the MSR, or if Windows cannot boot after the MSR was moved, you will need to delete and recreate it.

This is explained in this answer :

Boot into the Windows installation media, and press SHIFT+F10 to open the command prompt. Type diskpart. Type list disk, and then select disk X where X is the number of the physical drive containing the Boot partition. Type list partition to give you the partition list. I had the EFI System Partition at the start of the disk now which is 100 MB in size, and the partition list says that it began at an offset of 1024 kB. Windows considers a megabyte to be 1024 kB so the free space begins at an offset of 1024 + (100*1024) = 103424 kB. Type the command create partition msr size=128 offset=103424. If you have the sizes and offsets right, this should work, and in my case, it indeed did.

See also the description of the command Create partition msr.

harrymc

Posted 2016-07-28T13:10:32.597

Reputation: 306 093

Comments are not for extended discussion; this conversation has been moved to chat.

– Mokubai – 2016-08-04T11:14:22.563

Always backup before mucking with partitions.

Looks like his Windows partition is sdb4. If he adds the unallocated space to sdb4 (parted or whatever), then boots into windows, he should be able either to expand the drive inside windows to use the added space, or to add another drive using that space. Part of this will depend whether the Windows 10 drive was allocated with a dynamic filesystem (gpt) or a static one (mbr). – Xalorous – 2016-08-05T20:59:10.557

@af7: Your problem was solved, so where are you. – harrymc – 2016-08-06T08:44:55.910

1@harrymc My problem was solved, but - sorry to say that - not thanks to your answer, which I find not factually correct. Moving the MSR is not possible. It has an unknown filesystem and thus cannot be moved. You can clone it to another location and delete the original, but Windows will not boot. It is mandatory to use Diskpart: you have to recreate the MSR using Diskpart, or Windows will not boot. Thus while partially true and indeed providing good links, I find this answer not ready. If you want to edit the correct information in I'll be glad to accept it. Or if you want I can edit it. – AF7 – 2016-08-07T16:56:53.810

1@AF7: You may edit the text to your liking, no problem. Just that half of your bounty was lost. – harrymc – 2016-08-07T17:17:11.373

@harrymc I did edit, but my edit was apparently lost (or refused? I did not get any notification). :? – AF7 – 2016-08-11T07:39:30.250

Note for the readers: I have no idea what tool the poster used which refused to move a partition because it has an unknown filesystem. Most partition tools don't care much about the filesystem inside the partition. – harrymc – 2018-01-25T12:15:32.083

TLDR: Backup - this is a dangerous process. Then restore the disk, adjusting parititon sizes to taste.

The strategy I would take would be to back up first and adjust partition sizes when I restore. It seems a little odd, but firstly, its idiotproof (if you mess up, you simply restore) and many good backup software gives you the option to resize when you restore, and in many cases would fix the things that would break since its recreating the partitions from scratch.

Doing any sort of file system editing without a backup is irresponsible

My usual backup software's veem endpoint backup and - I've backed up, resized and restored and it seems to work for me -iirc you rightclick on the partition, and set the volume sizes and you're good. This isn't software designed for one off backups, so something else like macrium reflect might work as well.

Journeyman Geek

Posted 2016-07-28T13:10:32.597

Reputation: 119 122

However AFAIK no software can move, resize or delete the MSR without messing up with windows, except diskpart. – AF7 – 2016-08-04T07:25:54.970

@Journeyman Geek Just curious wouldn't creating new partitions and dump the content over creat new UUIDs and partition numbering? And in the process mess up GRUB und EFI boot loader? (And I'd suspect WIN boot loader too) – paradoxon – 2016-08-04T07:57:21.373

Windows loader should be fine, I've actually done this on EFI systems before. The idea being that the backup software would handle most of the wierdness, and grub is relatively easy to fix – Journeyman Geek – 2016-08-05T02:40:29.447

-1

If you don't want to mess with diskpart, you can do this in GParted. I tested this method on my machine and it works.

shrink /dev/sdb4 (windows partition) by 400MB (you've already done this)
unmount /dev/sdb2 (efi partition)
copy /dev/sdb2 into the empty space between /dev/sdb4 (windows partition) and /dev/sdb5 (linux partition) and call this new partition /dev/sdb7
enlarge /dev/sdb7 (new efi partition) to take the entire 400 MB
delete /dev/sdb2 (old efi partition)
ensure /dev/sdb7 (new efi partition) has the esp boot flag
if you use linux, update your fstab file to reflect the UUID of the new EFI partition

user966815

Posted 2016-07-28T13:10:32.597

Reputation: 1

1This would be a better answer if you gave detailed instructions — specifically for steps 1 and 3-7. – Scott – 2018-11-24T21:06:45.003