Getting Error for 2 (Two) EFI Partitions - Windows 10 + Pop OS

[Nitin]

Hi.

I have dual boot system with Windows 10 and PoP OS on same SSD. There are two separate EFI partitions for each OS. PoP OS does have its own bootloader SystemD. It is possible to use both OS but by pressing F9 each time to choose desired OS.

I wanted to install Android x86, for which I tried to install Grub2 on PoP OS, but it failed. It is giving BASH error and I am unable to use bootloader. Though both my Windows and SystemD bootloaders are working fine. Then I decided to use Grub2Win to edit Windows bootloader and use it for Android x86 dual boot.

But, since I have two EFI partitions and the second partition does not have any letter assigned and it is not mounted in windows system, the Grub2Win is showing error. I tried to assign letter using Mini Partition Tool but in vain. Please refer attached screenshot.

Please advise, how to use Grub2Win to create entries for the OS at one place.

Thanks in advance.

• Nitin

[Drummer]

Hi Nitin,

To fully understand your system, I need the Grub2Win diagnostics.

Please run them and send me the C:\grub\diagnose.7z file

Thanks,

Dave

On 7/24/2020 6:33 PM, Nitin wrote:

Hi.

I have dual boot system with Windows 10 and PoP OS on same SSD. There
are two separate EFI partitions for each OS. PoP OS does have its own
bootloader SystemD. It is possible to use both OS but by pressing F9
each time to choose desired OS.

I wanted to install Android x86, for which I tried to install Grub2 on
PoP OS, but it failed. It is giving BASH error and I am unable to use
bootloader. Though both my Windows and SystemD bootloaders are working
fine. Then I decided to use Grub2Win to edit Windows bootloader and
use it for Android x86 dual boot.

But, since I have two EFI partitions and the second partition does not
have any letter assigned and it is not mounted in windows system, the
Grub2Win is showing error. I tried to assign letter using Mini
Partition Tool but in vain. Please refer attached screenshot.

Please advise, how to use Grub2Win to create entries for the OS at one
place.

Thanks in advance.

• Nitin

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Getting Error for 2 (Two) EFI Partitions - Windows 10 + Pop OS
https://sourceforge.net/p/grub2win/discussion/general/thread/67ee4bf2bc/?limit=25#8f5d

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[Ed P]

Drummer, when replying via email please delete the email you are responding to.

Nitin, it is easy to have a single drive and a single EFI directory with multiple boot systems installed in it.

guest@porteus:~$ ls -g /mnt/sda1/EFI
total 24
drwxrwxrwx 2 root 4096 Jan 16  2020 Boot/
drwxrwxrwx 4 root 4096 Jun  2  2016 Microsoft/
drwxrwxrwx 2 root 4096 Mar 17 18:28 a1ive/
drwxrwxrwx 2 root 4096 Nov 25  2019 boot.backup/
drwxrwxrwx 4 root 4096 Jul 23 01:50 dell/
drwxrwxrwx 3 root 4096 Jan 16  2020 grub2win/
guest@porteus:~$ 

[Nitin]

Hi Ed P,

True, it is advisable to have only one EFI partiion. But I am very new to all these multiboot systems and all. I usually follow the processes given in tech blogs or vides uploaded on youtube. I found tow issues while installing Pop OS in dual boot with Win 10 on UEFI system:

1) While instsalling Windows can we increase the size of EFI partition? Because, in my experience I did not find a way to increase the size of default windows EFI partition. Maybe I am not aware about how to do it.

2) While installing Pop OS you need to create separate EFI partition. Maybe I am not aware how to install Pop OS on UEFI system with same windows EFI partition.

As far ass log files are concerned I have mailed them to Drummer. Request both of you to help me to resolve the issue. Thansk in advance.

[Drummer]

Hi again Nitin,

The assignment problem is not in Grub2Win. There is something wrong with partition 7.

Windows refuses to assign a letter to this partition. Possibly corruption in the partition.

You can verify this as follows:

From an administrative command prompt run diskpart

When the diskpart prompt comes up, enter these commands

select disk 0

select partition 7

remove letter O:

assign letter M:

If these commands fail, it means that Microsoft's diskpart utility could not assign a letter.
This usually indicates an error of some sort in the partition.

Note that Grub2Win does not assign the letter. It calls Microsoft's diskpart utility, so if diskpart fails, Grub2Win ends abnormally.

---

Expanding an EFI partition in Windows is quite a complex undertaking. I would not reccommend it unless you are very comfortable with manipulating partitions in Linux.

Please let me know if this works for you.

Thanks,

Dave

[Nitin]

Hi Dave,

I tried to change the letter of second EFI partition. I am able to change the letter using Diskpart. However, still after that I am getting same error from Grub2Win.

I am not able to understand, there was no letter assigned to Windows EFI partition & Linux (Pop OS) EFI partition. When Grub2Win started, it successfully assigned letter 'M' to windows EFI but failed to assign 'N' letter to linux EFI. When I assigned the letter manually to linux EFI partition as per your suggestion/procedure, I once again run the Grub2Win and this time it allotted letter 'O' to windows EFI and tried to allot letter 'P' to linux EFI and shwon same error, albeit with new partition letter.

I m unable to comprehend anything out of it. But, as mentioned by you, Diskpart is able to assign any letter to any partition except for ext4 formatted partitions used for Linux.

Please help here. I am sure, as Pop OS is getting popular, there would be many who have faced or will face similar issue in dula boot or trple boot systems.

Thanks,
Nitin

[Drummer]

Hi Nitin,

The failure is happening on the release of the letter. Here's the diskpart console listing from your run:

---

Input to diskpart

Select Disk 0
Select Partition 7
Remove Letter O:
Exit

---

Output from diskpart

Microsoft DiskPart version 10.0.19041.1

Copyright (C) Microsoft Corporation.
On computer: DESKTOP-C19N3KO

Disk 0 is now the selected disk.

Partition 7 is now the selected partition.

There is no volume selected. < This is the error
Please select a volume and try again.

---

Microsoft does not support multiple EFI partitions on the same disk drive.
I think this may be causing the diskpart problem.

You could try manually removing the letter on Disk 0 Partition 7 and running again.

In any event, Grub2Win can not work if diskpart has errors.

I reccommend you consolidate your EFI partitions.

Please let me know.

Thanks,

Dave

[Ed P]

Consolidating the EFI partitions might be tricky. On my system my EFI partition has a EFI folder and a Boot subfolder. The Pop-OS system has an efi folder and a boot subfolder. Does EFI follow Wndows' naming standards or Linux's? If the latter, no problem copying the Pop-OS boot folder to the EFI folder.

Maybe booting the ISO might be a better option.