Hardware Others Why does my BIOS think that the internal HDD isn't bootable?

[jeffyTheHomebrewer]

So, recently had to replace the PSU in my server because it just croaked one day while I had the server off. So that was just great. Thankfully had a spare of the same spec, but now it doesn't see the internal 320gb HDD as bootable, despite the fact that the mobo can see the drive!
It's got three partitions on it:
A small fat32 partition
An EXT4 partition
A swap partition
Those last two are for OpenMediaVault (debian-based linux, really good for setting up a home server imo) and I THINK the fat32 one is boot-related, but the motherboard DOES support UEFI...
I can at least boot to gparted from a USB drive, and then boot into OMV on the HDD from there.
Also used gparted to give the EXT4 partition the boot flags. That did nothing.

Normally, I'd just back up all my stuff on there, then nuke the disk and install OMV anew, but I can't because I have no drives to hold everything!
That and setting up OMV the exact same way again would be a bit of a pain in the ass, so..

Anyone here got any idea of what to do so I don't have to use a gparted-live USB drive to "jumpstart" the server into booting up OMV? Because having to stand there EVERY time it reboots (not often, but sometimes it needs to) is getting annoying now.
It's been like this for about a day or so, but the PSU was dead for about 3 days before I replaced it because I noticed that the server wasn't turning on.

 

[master801]

I'd say to reinstall GRUB.

 

[jeffyTheHomebrewer]

I'd say to reinstall GRUB.

...and how exactly do I do that without also having to reinstall linux/OMV entirely?
I can make my way around the terminal, sure, but I'm not the best with linux. I mainly use Windows for things but Linux is better for compatibility with other OSes as a server.

 

[master801]

...and how exactly do I do that without also having to reinstall linux/OMV entirely?
I can make my way around the terminal, sure, but I'm not the best with linux. I mainly use Windows for things but Linux is better for compatibility with other OSes as a server.

I'm not exactly sure with OMV, but this might be useful?
https://docs.openmediavault.org/en/5.x/installation/via_iso.html#troubleshooting

Might need to boot into OMV first then run the commands. If you're unfamiliar with Linux/Debian, MAKE SURE YOU KNOW YOUR DRIVE PATH BEFORE USING THE grub-install COMMAND!

 

[jeffyTheHomebrewer]

I've fixed it! Though, not really by reinstalling grub. I've ended up just putting rEFIned in its place, since it more or less does what I need (autoboot to OMV) even if somewhat slower than grub. Sure, maybe rEFIned is a bit overkill here, but seeing how it automatically saw that Debian (omv) was there, AND how it had an install to disk option, well... I just let it overwrite the fat32 partition that Grub used to live on and now it all just.. works!