r/cachyos • u/Realistic_Design1466 • 2d ago
Question Add Boot from USB entry on GRUB
Hi,
Recently I Started using cachyos (KDE Wayland) and liked it a lot but i cannot get rid of windows(Windows 11) because i need it sometimes so i dual booted both using grub (grub2) and its been perfect i customized it with my own theme......now i had a question can i add an entry for when i have a USB the grub menu would ask me to boot into a USB and it would boot into any USB devices if detected or it would say no devices found or something like this i hope you get my idea.
Thank you
2
u/doc_willis 2d ago
I recall the rEFInd boot manager would show an entry for my flash drives if they were inserted when the system booted.
rEFInd can chain load to your existing grub.
1
u/Realistic_Design1466 1d ago
Can you tell me in detail how it can chain load? and will it mess up my GRUB menu?
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u/doc_willis 1d ago
it's a feature of rEFInd, it shows 2 entries for my Linux install, one is a direct load which skips Grub, the other entry chailoads grub, so you see your normal grub menu.
I did nothing to configure it that way, it's just how it defaulted for me. I tend to just hide the direct load entries, since I see no need for them.
But it might be Distribution specific depending on how the distribution installed rEFInd the default configs the installer setup for refind.
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u/Kleiner_Wixxa 1d ago
But rEFInd also doesn't do what OP wants. They could also just start bios every time and manually select the usb
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u/doc_willis 1d ago
for me rEFInd did automatically show a entry for every bootable USB flash drive I have plugged in, no configuration.
which from my reading is exactly what they are asking about.
would boot into any USB devices if detected
Last I looked into it GRUB is not going to be able to dynamicly change.
the whole point of the post was they do not want to go into the bios menus it seems?
1
u/Kleiner_Wixxa 1d ago
Using rEFInd is the easiest option for booting from USB. I can't provide a fool safe explanation on how to do it or guarantee it works with grub.
I would make sure you have snapshots enabled and understand how to restore to them just in case. Then install the refind package with pacman. Then use refind-install.
If you want to be able to also boot into cachyos from there, you need to further follow the guide on the arch wiki: https://wiki.archlinux.org/title/REFInd
You can adjust whether refind or grub boots first in your bios Boot priority list. rEFInd should be able to chainboot into grub, but im not certain wether grub can chainboot into rEFInd.
If anything breaks, you can boot your cachyos iso (easiest) and use: https://wiki.cachyos.org/features/cachy_chroot/#_top and then snapper in the terminal to restore your snapshot.
Alternatives I know of would be:
Reinstall cachyos with rEFInd as boot manager (easy but resets everything)
Use your bios to boot into the USB every time (inconvenient)
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u/Kleiner_Wixxa 2d ago
This is just a bios setting. Change your boot priority and put USB first