Bootloader files for mint keep ending up in the windows efi partition.

[river tendon]

I have a desktop (i7-9700k/PNY RTX2080Ti) that is running windows(on nvme1) most of the time but has had a couple different flavors of Linux running successfully on other drives before (zorin, Ubuntu, an older version of mint). When trying to install Mint 22 Cinnamon V6.2.7 Kernel:6.8.0-38-generic I have been pre partitioning the drive I want it on. Giving it a 1 GB fat32 efi partition with boot and esp flags, a 75 GB ext4 / partition, a ~900 GB ext4 /home partition, and a 32 GB swap partition. Sda1 through sda4 respectively. I designate the sda1 efi partition during the install choosing the "something else" option, and the install commences without a hitch. However, upon successful install and reboot into the UEFI BIOS it shows the Ubuntu boot as being on the nvme which I can see when I checked the nvme partition and found the Ubuntu bootloader files. I have tried without the sub partitions for / and /home, as well as putting all of them as logical partitions under 1 large extended partition.

Reproducing-
-set up partitions on an empty second drive with ample room with gparted on a live instance of mint 22 Cinnamon on a usb that has been integrity verified.
-run install and choose the something else option where I set the 75 gb and 900 gb partitions to the / and /home mount points.
-set the device for bootloader installation to dev/sda1 which is the 1gb efi partition (I have also set it to the whole device of dev/sda instead of the partition with the same result)
-complete installation and open UEFI BIOS on reboot to see Ubuntu booter on the windows drive.
-boot into the live usb again and mount the relevant partitions to see the second drivers efi partition unused, but all other Linux files there and the Ubuntu bootloader in the windows efi partition.

What I expected: The Linux installer to put all os files on the second drive that was pre-partitioned.

What happened: The Linux installer put everything except the bootloader onto the second drive.

Any assistance is appreciated! I'm happy to provide more information if needed. Thanks!

[stoic portal]

it shouldnt matter unless u plan on removing the Windows drive or it is close to dying. check the DISKS app to see the true active system partitions, shown with a star icon

[proper wren]

are you sure sda1 partition is set as "EFI system partition" in the installer?

[river tendon]

Yeah, formatted to fat32, and manually picked as EFI system partition in the installer. Flagged with boot and esp flags with gparted before running the install.

[proper wren]

that's not what I asked for. is the partition set as "EFI system partition" during the setup, in the installer, in the custom partitioning screen, when you double click on it?

[river tendon]

Yes. That is what I mean when I say it was manually set. I right click on it and set EFI system partition which removes the drop downs for setting mount point and greys out the option to have the installer format the partition as part of installation.

[proper wren]

yes, exactly what I meant. then it means the installer is stupid and is somehow overriding your commands, possibly due to some incompatibility or you setting it up incorrectly. if your drive is blank, "erase and install" option should do the trick.
you can also remove the windows drive during install, then it psychically won't be able to install to it.

or just use the shared EFI and don't care about it

[river tendon]

Ok! Fair enough. I'll turn the nvme off in the BIOS, and let it run through again. Thanks!

[stoic portal]

in the manual mint installer, u absolutely must choose the Device along with its PARTITION NUMBER , in the dropdown field for "location for bootloader". if the wrong one is chosen, or just a disk name is chosen, it defaults to whatever u got.