(Ubuntu 23.04) Can't find the option for installing bootloader on different partition

[benasd]

Here is my partition table
sda 931.5G
├─sda1 16M
└─sda2 BitLocker 931.5G
sdb 28.7G
└─sdb1 vfat 28.7G
nvme0n1 953.9G
├─nvme0n1p1 vfat 100M
├─nvme0n1p2 16M
├─nvme0n1p3 BitLocker 660.1G
├─nvme0n1p4 ntfs 683M
├─nvme0n1p5 vfat 300M
└─nvme0n1p6 ext4 292.7G



I'd like to install bootloader on nvme0n1p5 and mount / on nvme0n1p6


The option to install bootloader on a particular partition seems to be removed. When I select nvme0n1, it automatically mounts nvme0n1p1 to /boot/efi, which is not what I want.



There used to be an option to use a partition as EFI partition in the older installers, but I can find it in the newer one.


Is there any way to installer bootloader on nvme0n1p5? Or any workaround?

[sudodus]

Use the legacy iso file

cdimage.ubuntu.com/releases/lunar/release/ubuntu-23.04-desktop-legacy-amd64.iso

with the following sha256sum:

0cef2280b3d8710733231d1ad1c72474e6bbc41a0d8d2ea69f7728f3d60fb786 *ubuntu-23.04-desktop-legacy-amd64.iso

This iso file has the old installer 'Ubiquity' which is well known and tested for decades.

It is a good idea to get the file via torrent:

cdimage.ubuntu.com/releases/lunar/release/ubuntu-23.04-desktop-legacy-amd64.iso.torrent

[oldfred]

Most systems only support one ESP - efi system partition per drive/device.

Grub does not care, so you can do a work around by removing esp,boot flags from Windows ESP, install grub and move esp,boot flags back.
UEFI will have GUID of both ESPs in UEFI boot entries. Not sure if issues with updates later.

Ubuntu's Ubiquity installer only installs to ESP on first drive, whatever system defines as first drive. With NVMe drives that usually is first, otherwise sda.

[ubfan1]

"This iso file has the old installer 'Ubiquity' which is well known and tested for decades." -- and which never worked for installing bootloaders to a second disk. See bug https://bugs.launchpad.net/bugs/1396379 The change apparently allows this, but haven't run it myself.

[benasd]

Thanks for the replys, I managed it get it working with a workaround.

Here's how I did it:
Remove "boot, esp" flags on windows boot partition(nvme0n1p1 in my case) in GParted, and then add the flags to the partition(nvme0n1p5 in my case) you want to install bootloader on.
Go ahead installing Ubuntu, now when you select nvme0n1, the installer will use nvme0n1p5 as EFI partition by default, if it doesn't, click on "revert" in the installer, the installer will refresh and use the new partition settings.
After finished installing Ubuntu, do not reboot right away. Go back to GParted and re-enable "boot, esp" flags on windows boot partition(nvme0n1p1 in my case). Now we have 2 EFI partition, the workaround it completed.

Noted that if you forgot to to the last step(re-enable "boot, esp" flags), Windows will mount it's own bootloader partition as a data partition, potentially corrupting it.