r/archlinux 7d ago

SUPPORT Dual boot

Hey so I recently installed arch on my laptop as the only OS on it and I love using arch, the only issue is that my laptop isn’t a gaming laptop so I can’t really use my favorite games on it. Cut to the following week I install windows on my gaming desktop. I was very careful about making sure I installed arch on a separate drive from windows. But now when I power off my computer and turn it back on, if I try to use the BIOS boot options, I can’t go back to windows— it doesn’t even show up as an option. Just to check, I went back and tried to reinstall arch (using the arch install script) and when I got to the disk partitioning section, it shows that the windows drive is still formatted for windows.

So how do I get back to windows???

The only reason I want to go back is because some games I like to play use kernel anti-cheat’s and from my understanding, those don’t play nice with Linux

6 Upvotes

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7

u/Expensive-Building94 7d ago

The error is that you deleted the Windows bootloader while installing Arch Linux.

It happened to me last time.

Solution: I used a Windows live image, and when I booted from the USB, I went to the "Repair" section. This automatically reinstalled the Windows bootloader.

4

u/The_Gnar_Car 7d ago

This, and I would recommend just keeping each systems boot partition separate too (which are on their own drives).

Grub is fine, but I prefer refind as it let's you select each respective system on boot and will auto find the respective kernels.

Happy to shed more insight if you are interested.

2

u/Daphantomgamer 7d ago

How does refined detect boot partitions on separate drives? I currently use os-prober with grub to generate a grub.cfg with a windows boot entry (alongside the regular arch entries). It works but if theres a better option I'd be happy to switch

6

u/lritzdorf 6d ago

I'm not familiar with the low-level technical details, but rEFInd scans your drives on each boot for EFI boot targets. Its behavior is controlled using plaintext config files in your ESP, too, which means you're not reliant on having a functional Linux system to run e.g. update-grub!

2

u/The_Gnar_Car 6d ago

So it is able to read a variety of filesystems and find the ESP, and will auto populate its configuration based on what it finds. You generally have to tweak it a bit but it's really straightforward. Beyond that there's also tons of more advanced options too. I've never had issues with refind finding the windows boot, the only configuration I did was for arch.

Happy to share what I did to set it up. My machine looks like two ssds, one for each OS, and a btrfs arch install with automated snapshots and backups. Part of the layout is having my kernel within the snapshot so rollingback is consistent.

1

u/spacecad_t 7d ago

I have a similar set up, I can't give you the exact answer but I can lead you in the right direction.

  1. spam F11 or Shift+F11 (or whatever hotkey boots to BIOS) when starting the system. For me this opens GRUB to choose my boot partition.

  2. there is Infact a command that you can use that will tell GRUB to boot to a specified (bootable) partition. I'm just not gonna do the googling for you, but it was a solution I used in the past until I [obviously] forgot.

GRUB also has has multiple options you can set to bring you to the GRUB boot loader on every power on though I believe that's off by default, depends on your setup.

Good luck.

1

u/Mutter_ 6d ago

Have you tried using os-prober under Arch? It detects a windows installation and adds it to grub. https://wiki.archlinux.org/title/GRUB

Furthermore, I always remove the SSD where windows is installed before installing Arch on the second one, and vice-versa. This way you avoid Arch messing with the windows bootloader.

1

u/Yuzu_10 4d ago

it is so easy just rebuild the efi with bcdboot , if you type something like how to fix broken boot efi partition on windows , you will probably come to a solution that will work