Help to boot directly off m.2 drive instead of my hdd where the bootloader is. ASUS A520M-K

Question

Good day all

I am stumped... So I was running an older system on PopOS(From an HDD), I upgraded and decided to install ElementaryOS on my SSD, the HDD was still plugged in, when it came to choosing where to install, I chose the SSD and just let the installer decide how to partition.

Now I did find it odd that the SSD was not showing up in the Boot section of the BIOS, even after successfully installing an OS... So it boots to the HDD, grub loads and I select ElementaryOS and it boots fine from the ssd from there... Now my problem is this.

I would love to just format the entire 4TB drive to use it for storage(it's currently still encrypted from previous install and I have to unlock it everytime I need to access it).
I already have all the data I needed from it backed up, but I am not sure how to format it and not mess up the weird boot situation, or how to get the mobo to boot directly off of the SSD (Again, the ssd is not listed as a boot device, even override, BIOS version is most recent non-beta). I have tried a few settings in BIOS but none have helped. Secure boot is set to OtherOS(If that matters).

I spent a bit of time setting up things on the OS now and would prefer a fix rather than a reinstall. It's also my first m.2 install ever, I just assumed it would function as a normal SATA device but apparently not. I have only been a full-time Linux user for around 9 months now(Loving it).

Should the SSD be set as a primary? If so how can I do that? Here is some fdisk -l output:

Disk /dev/sdb: 477 GiB, 512110190592 bytes, 1000215216 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 47942DB9-2DCD-4EF8-AD14-691553C783F4

Device Start End Sectors Size Type
/dev/sdb1 2048 1050623 1048576 512M EFI System
/dev/sdb2 1050624 1000214527 999163904 476.4G Linux LVM

Disk /dev/sda: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 70C4DE00-B732-4335-BEB7-E0300D91CFB5

Device Start End Sectors Size Type
/dev/sda1 4096 1023998 1019903 498M EFI System
/dev/sda2 1024000 9412606 8388607 4G Microsoft basic data
/dev/sda3 9412608 7805644462 7796231855 3.6T Linux filesystem
/dev/sda4 7805644464 7814033070 8388607 4G Linux swap

Answer 1

So we you need to narrow down some possible unwanted settings and behavior first.

1. I assume the ssd drive is shown in the bios, when showing drives?
2. I assume u already set the ssd as boot device

If that is done and no change, you could install grub-customizer on the popos install and see if an eOS entry is set. If not, create an eOS entry with it.

See here for more detail on how to do so.

Answer 2

Okay so...

I managed to solve the problem. UEFI and m.2 drives apparently need an ESP partition with correct files in it to recognize it as bootable, otherwise, it will only list it as a connected device in your BIOS, not as a boot option.

I installed boot-repair: https://www.fosslinux.com/1521/boot-repair-for-ubuntu-linux-mint-and-elementary-os-can-fix-bootloader-issues.htm

Then I used it to give me a report, the SSD did have an ESP partition but was empty(thus not selectable as a Boot device in my bios)

I then ran boot-repair again selecting advanced options, and GRUB Location, I set it from sda to sdb(the latter being the SSD), but that messed something up...(NVRAM LOCKED)

So I booted into the Elementary Live USB and followed again the installation as described here: https://www.fosslinux.com/1521/boot-repair-for-ubuntu-linux-mint-and-elementary-os-can-fix-bootloader-issues.htm

I followed the same procedure as before with the advanced settings, making sure to copy the commands into the terminal and being patient as boot-repair gave them to me.

I restarted the machine and went into the BIOS and viola! My SSD is there, booted right off it with Grub 2, and no problems... Now I can finally reformat my 4TB.

I still would not be able to do something like this without a tool such as boot-repair though.

From what I can gather, having another drive with an esp partition present during install will prompt the automated installer to just use that current one for the boot loader, even though it created one on the target drive... I might be wrong, but this is what I understand from all I have read/done.

So when installing an OS to an m.2 drive, make sure all other drives are disconnected.