Q4OS Forum

Edwin

Member

Registered: 2025-12-21

Posts: 4

Won't boot, dropped to GRUB prompt

First of all, after a short night with 6 frustrating hours of trying to fix it, I finally decided to just reinstall Q4OS, but I still would want to know how to solve this, in case it happens again.

Somehow the PC wouldn't boot anymore and threw me a GRUB prompt. I tried "everything" I found on the internet to solve this, but to no avail.

It seemed that somehow GRUB forgot what "EFI" to start. But I could start it manually and get the GRUB boot menu by choosing "select file" at the boot selection:

* PciRoot(0x0)/Pci(0x17,0x0)/Sata(0x0,0x0,0x0)/HD(1,GPT,D662A3CB- ... (some guid, not displayed entirely?)
* EFI
* Q4OS_Andromeda
* grubx64.efi

Checking GRUB settings, root (hd0,gpt1) and prefix ((hd0,gpt1)/EFI/debian) seemed incorrect; should be (I think) 'hd0,gpt5' for root and '(hd0,gpt5)/EFI/Q4OS_Andromeda' for prefix.

The settings for the Q4OS entry seemed correct; if I manually started grubx64.efi I got my normal menu and could start Q4OS. And GRUB started, although with a command prompt, so the correct bootloader (in UEFI) is selected.

It's just that grub must have some configuration somewhere that tells it to start the EFI in '(hd0,gpt5)/EFI/Q4OS_Andromeda', but I couldn't find anything on the internet to tell it to use that and persist it for subsequent boots...

Anyone any idea?

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,114

Website

Re: Won't boot, dropped to GRUB prompt

What way exactly did you install Q4OS ?

Edwin

Member

Registered: 2025-12-21

Posts: 4

Re: Won't boot, dropped to GRUB prompt

First I installed Windows 11, leaving 32 GB diskspace free. Then I installed Q4OS by booting from USB and choosing for "Install". Then I tried installing ChromeOs Flex to a pendrive, with the SSD disconnected. After that, I removed all pendrives, reattached the SSD and booted again.

I think that ChromeOS Flex caused the confusion, although the SDD was disconnected during install of ChromeOS Flex.

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,114

Website

Re: Won't boot, dropped to GRUB prompt

... I installed Q4OS by booting from USB ...

- We would need to know the .ISO file you used for the installation.
- Did Q4OS boot and work at least once before the issue occurred?

Mzungu

Member

Registered: 2026-01-03

Posts: 1

Re: Won't boot, dropped to GRUB prompt

May I second here:

Q4OS installation worked like a charm for a few days testing from a SD-card — kudos to you!

Now I also have to select EFI to boot — after I installed a different Debian-distro on a different SD-card as giveaway…

Maybe a BIOS thing? But reset to defaults, no avail :-(

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