I have to do it. I hate to do it.. it felt dirty lol..

But there's a few things Imma need (small software, like Deios, a couple early alpha indie games..) and I just can't get adequate performance in a VM (maybe when I have the cash for a new GPU I'll see about setting up passthrough and-- well, that's for another time..)

Anyways. I have a dedicated hard drive for windows. All installed properly, I think but when I boot up, I can't log into windows or solus. Ot shows an underscore (oof, there's a painful flashback...) then that entire.. line? turns into static (like if you changed the chanel when TV was chanel 3, but minus the noise from nightmares). Unplugging the drive with windows installed lets me boot into solus just fine, so I'm assuming it's an issue with MBR/Grub/whatever conflicting but I'm not really sure how to test/fix that..

Can I get some assistance?

Oh, also... I was considering googling around on how to fix Grub but I wasn't really sure if y'all Even used Grub, for some reason I'm thinking Solus doesn't.. but I gotta crash out so if someone happens to just know what's up great, if not, I'll have to play around with this tomorrow and see if I can figure something out.

I just keep everything separate and use the UEFI boot menu.

Okay, I just woke up, making some breakfast as I dive into this...

So first things first, it looks like I'm on the right track ab out the Boot Menu being the issue? That'd be, GRUB, or something..
I think I've got some ideas on things I should have known already, so I'm gonna start by figuring that out real quickly.. around the process of eating, that is.

First: Figure out what boot menu Solus is using.
Second: Figure out if I'm on UEFI Boot or Legacy Boot

Huh, also apparently my time broke during that process. Clock is 8 hours behind, for some reason- easy to reset, but may or may not be related so gonna go ahead and mark it here for posterity... probably a coincidence, though...

Found a thing saying you can see if your hard drive is in EUFI by typing "ls /sys/firmware/efi" into console (this was made for ubuntu though..) and it says "file not found" meaning it's not on EUFI.

Assuming that's accurate for Solus, then I'm on legacy boot, so if windows is on EUFI is that a problem? Does it need to be on Legacy boot as well? I assume I can't just "upgrade" to EUFI on Solus (reeeallly not trying to re-install Solus..)

And how do I install Win10 under Legacy boot rather than EUFI?

Okay, so my HDD is a 4TB drive, so it has to be EUFI... so assuming Solus is in fact not EUFI (it's on a 2TB SSD.. which apparently means it can be either..) Am I just SOL, can I have Solus on legacy, and windows on EUFI, can I...

What are my options here?

lmao yeah, I figured this would be a process! It's just that not having my extra HDD now, I can't back up all my stuff as easily so I'm a bit more apprehensive 😅

I had searched it before on here, and it looked like it was a struggle, but it also looked like most of the issues were caused by trying to have separate partitions on the same disk; of course, naturally that means a lot of the solutions are for that as well, but I'll check those out and see if I can figure out something, or at least some next steps, thanks!

Seems a bit too simple but.. looking at those, it seems as if I just delete the ESP from the windows HDD my Solus ESP would "pick up" on the other OS, but idk if that would actually happen given the OS is on a different disk than my ESP..

only thing that really looks like it might be able to help is the line:

If I were you I would just create another EFI boot partition, in gparted (flag it esp, boot)
install solus and choose the new EFI partition when asked about bootloader
and copy the Microsoft directory from the old EFI to the new one

Idk if I'd be able to copy the EFI from Disk 2 to Disk 1 and have it so that Disk 1 could send me to Disk 2, though, but... I guess it's something to look into further.

Oh, or maybe ESPs are only used in EUFI systems (my solus being a BIOS), so it wouldn't have an ESP that I could copy the windows ESP contents to...

https://getsol.us/articles/installation/disks/en/
the big quote is from this link. This pretty much is how Solus says your situation must look like before attempting any install next to windows.
I should shut my yap now since I have never attempted this, but the ESP delete looks scary.

"Solus provides multiple ways you can install onto your system.

1)Solus can take up the entire drive, using traditonal root partitions, or with LVM-managed root partitions.
2) You can install Solus next to your existing operating system, such as Windows. If you have multiple operating systems installed, we will choose the largest option.
3)You can manually configure your system. This is only recommend for advanced users which may desire to have a dedicated /home partition. Note that if you manually configure your system, you will need to restart the Installer for those changes to apply appropriately. Note: Legacy (BIOS) must use MBR partition table while Unified EFI (UEFI) must use GPT partition table.
Alongside these options, we also provide the ability to use full-disk encryption. For the obvious reason of it being full-disk, this assumes you are installing Solus onto the entire drive.

UEFI
If you are using a system with UEFI, you may need to create a EFI System Partition, also referred to as an ESP. This is not necessary if you are enabling Solus to install onto the entire disk.

To create an EFI System Partition, open up GParted and create a FAT32 partition that is 512MB in size. Next, right-click on the partition and click Manage Flags. On the Manage Flags section, enable the boot and esp flags.

Notes:

Your system must be booted using Unified EFI (UEFI) mode, as opposed to a “legacy (BIOS) mode”.
Secure Boot needs to be disabled.
Your disk is required to be GPT formatted.
If you cannot see your SSD drive, set the SATA configuration to AHCI."

This is the condition you are supposed to begin installing in. I hope one of the forum users who has done this successfully will chime in.
edit: the bullet points did not survive cut and paste

yeah, that's requiring a EUFI set up, which mine isn't.. So that would bring me back to the question of can I upgrade from BIOS to EUFI, to start at that point (or, ofc, reinstalling..)

https://unix.stackexchange.com/questions/252936/grub2-boot-to-a-second-another-hard-disk

From this, trying user os-prober to update Grub. I do have a place to edit grub, so I'm just gonna assume that's what I'm using, as I'm not on EUFI... since Solus only seems to offer much advice if you're using a EUFI, so there's not much I can do to get around that it seems, shy of a clean install.. Hoping to find a way that doesn't require that, but eh.. we'll see.

It said it recognized windows 10 but didn't give me the option to boot into it

Oh, it says to put in this afterwards: grub2-mkconfig -o /boot/grub{2}/grub.cfg

However, Konsole says "grub2-mkconfig: command not found"

Over here boutta break something I think buuuut gonna just remove 2 from that.... so it's

grub2-mkconfig -o /boot/grub{2}/grub.cfg

Hm. Well, command found, but no file found....


Try just

grub-mkconfig.

oh, that did something. Lots of words... Time to cross my fingers reboot and see what happens, I suppose!

Still no ability to boot into windows, although I forgot to mention I am not having it crash after plugging in the Win10 HDD anymore, it just directly boots into Solus so that's nice.

Few reboots messing around with trying to boot into second HDD via f12, for some reason it just kept not letting me do that... Finally went ahed and ran os-prober than grub-update (...or was it update-grub? Uhh..)

Anyways I can see windows 10 now!!

Unfortunately, it's still having the issue of the actual windows 10 partition is messed up, but that's possibly a seperate issue.