Ubuntu – How to install a Ubuntu dual boot with Windows 10, when the UEFI partition is NTFS

dual-bootntfspartitioningsystem-installationuefi

I have recently received a machine with a OEM Windows 10 installed.
But I couldn't install Ubuntu on it, because the UEFI partition was in NTFS format.
Instead of vfat/fat32 like the the UEFI specification stipulates. NTFS is not even mentioned there.
But like always: Microsoft is bigger than any international standards, so others need to adapt.

I tried different methods to recreate the UEFI partition, but I couldn't get it working without removing the Windows installation. I was considering to reinstall Windows 10 and try to force the UEFI in FAT format.

But I was able to talk the customer/user out of using Windows natively, since he only needs this to Admin Windows servers and simulate problems of Windows users/customers. Remmina will do to connect to the Windows servers and virtual machines will do to simulate Windows software problems.

Still I think it would be a good idea to collect workarounds/fixes for the dual boot with NTFS UEFI partitions. Since I fear I won't be the only person confronted with this issue.

Best Answer

EDIT: Turns out, the below was "false alarm" of sorts; somewhat later, I realized the disk hosting this NTFS "EFI" partition is formatted MBR, not GPT; and it does not have an EFI folder either, nor typical expected Windows EFI files as EFI/Microsoft/Boot/bootmgfw.efi. I guess, the presence of the "esp" flag on this partition is what got me confused.

In the end, I ended up doing this:

  • First installed Ubuntu on a spare partition from an EFI booted USB, and ignored fails in installing grub on NTFS
  • I hoped that I could flash GRUB2 manually on NTFS partition, but grub2 2.04 has explicit check for FAT, so that is for the time being impossible:
if (!efidir_is_mac && grub_strcmp (fs->name, "fat") != 0)
  grub_util_error (_("%s doesn't look like an EFI partition"), efidir);
  • Then I tried recommendation in comments:

To change the off ntfs EFI partition, just copy the files off, change the partition type and reformat to FAT, then copy the files back

This still didn't help dual boot at this point, however, now that I had a FAT32 partition, I could re-install Ubuntu, from stick booted in EFI mode, while flashing GRUB2 on this partition.

  • Now Ubuntu did start up, but os-prober simply did not detect Windows at all; boot-repair did not correct anything, but it mentioned that it saw "legacy windows"
  • Finally, from the Ubuntu installation, I re-installed grub2 on the partition, but with --target=i386-pc; and forced legacy-only boot from BIOS
  • Rebooting into Ubuntu now, boot-repair removed all grub EFI-related packages - and finally, os-prober could see Windows partition; but the entry it added (with chainload) could not boot into Windows, claiming disk was not bootable (which it isn't, as the Windows install is on partition 2, which is not marked bootable)
  • Finally, as per suggestion in How to boot into Windows 7 when grub is installed in the Windows partition? - I added manuall a Windows 10 entry which used ntldr ($root)/bootmgr - and finally I have dual boot!

Which is to say - this first NTFS partition, which was bootable (and marked esp) was most likely not a real EFI partition - maybe it somehow facilitated recovery or something; which is (I guess) proven by the fact, that I could only achieve dual boot to Windows, by forcing legacy boot.

Not an answer, but just wanted to respond to this:

I'd like to see the output of sudo parted -l and sudo blkid on this system with the allegedly-NTFS ESP. I've seen such claims a couple of times before, but without evidence. ...

Please provide the parted -l and blkid output first, though; that could provide vital information.

Yup, just ended up with a system like that, refurbished ThinkPad.

I booted up Slax on my USB thumbdrive on this laptop (in legacy mode), and it provides this information (note that I've done a bit of manual partitioning, in addition to what was present upon disk already; I've also removed info about other drives):

root@slax:~# parted -l
Model: ATA KINGSTON SUV400S (scsi)
Disk /dev/sda: 120GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags:

Number  Start   End     Size    Type      File system     Flags
 1      1049kB  368MB   367MB   primary   ntfs            boot, esp
 2      368MB   54.1GB  53.7GB  primary   ntfs
 4      54.1GB  118GB   64.4GB  extended
 5      54.1GB  75.5GB  21.5GB  logical   ext4
 6      75.5GB  108GB   32.2GB  logical   ntfs
 7      108GB   118GB   10.7GB  logical   linux-swap(v1)
 3      118GB   120GB   1611MB  primary   ntfs            diag

So, partition 1 is marked both as ntfs, and as boot & esp.

root@slax:~# blkid
/dev/zram0: TYPE="swap"
...
/dev/sda1: LABEL="System" UUID="64C89227C891F78E" TYPE="ntfs" PARTUUID="5e4a12da-01"
/dev/sda2: LABEL="Windows" UUID="EE3E98553E9818A3" TYPE="ntfs" PARTUUID="5e4a12da-02"
/dev/sda3: LABEL="Recovery" UUID="28DE98A6DE986E36" TYPE="ntfs" PARTUUID="5e4a12da-03"
/dev/sda5: UUID="80bbb011-a20f-489f-99dc-bbcc9422f7f4" TYPE="ext4" PARTUUID="5e4a12da-05"
/dev/sda6: LABEL="XXXXXX" UUID="3BBF7C062DC0E351" TYPE="ntfs" PARTUUID="5e4a12da-06"
/dev/sda7: UUID="abf91577-e9e8-4cd5-9e3f-48393f6c084c" TYPE="swap" PARTUUID="5e4a12da-07"
/dev/sdb1: UUID="D4D5-9DAC" TYPE="vfat" PARTUUID="000568d1-01"

I wanted to install Ubuntu dual-boot on this machine along with Windows, so I booted up the mini.iso from USB thumbdrive (in EFI mode), which runs the text installer; originally it showed this state of partitions:

textinst-parts-01

I then tried to to set up partition 1 to be "Used as" EFI system partition, which resulted with this state being shown:

textinst-parts-02

... however, the text installer would have none of it - and it failed with "The attempt to mount a file system with type vfat in SCSI2 (0,0,0), partition #1 (sdb) at /boot/efi failed.":

textinst-parts-03

So, yeah - the text installer does seem to make the assumption that the EFI partition is always vfat, and as in this case it is NTFS, the process there fails ...

So I cannot really tell, what I can do, to have Ubuntu installed on this system in dual boot configuration with Windows - without changing the EFI partition ...

EDIT: Here are approximately the files present on this first NTFS partition, mounted on /mnt here (I had cut off some obvious translation and font files to make it easier to read) - note that there is no EFI folder anywhere:

$ tree /mnt/

/mnt/
├── Boot
│   ├── BCD
│   ├── BCD.LOG
│   ├── BCD.LOG1
│   ├── BCD.LOG2
│   ├── bg-BG
│   │   └── bootmgr.exe.mui
│   ├── BOOTSTAT.DAT
│   ├── bootuwf.dll
│   ├── bootvhd.dll
│   ├── cs-CZ
│   │   ├── bootmgr.exe.mui
│   │   └── memtest.exe.mui
│   ├── da-DK
│   │   ├── bootmgr.exe.mui
│   │   └── memtest.exe.mui
...
│   ├── Fonts
│   │   ├── chs_boot.ttf
│   │   ├── cht_boot.ttf
...
│   │   ├── segoen_slboot.ttf
│   │   ├── segoe_slboot.ttf
│   │   └── wgl4_boot.ttf
│   ├── fr-CA
│   │   └── bootmgr.exe.mui
...
│   ├── memtest.exe
│   ├── nb-NO
│   │   ├── bootmgr.exe.mui
│   │   └── memtest.exe.mui
...
│   ├── Resources
│   │   ├── bootres.dll
│   │   ├── da-DK
│   │   │   └── bootres.dll.mui
...
│   ├── ro-RO
│   │   └── bootmgr.exe.mui
...
│   └── zh-TW
│       ├── bootmgr.exe.mui
│       └── memtest.exe.mui
├── bootmgr
├── BOOTNXT
├── gboot
│   └── grub
├── grub
├── manboot
│   ├── bcd
│   ├── bootfix.bin
│   ├── boot.sdi
│   ├── efisys.bin
│   ├── efisys_noprompt.bin
│   ├── etfsboot.com
│   └── fonts
│       ├── chs_boot.ttf
│       ├── cht_boot.ttf
│       ├── jpn_boot.ttf
│       ├── kor_boot.ttf
│       └── wgl4_boot.ttf
└── System Volume Information
    └── tracking.log
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