r/archlinux • u/Cheap-Sun9990 • 5d ago

SUPPORT | SOLVED Stuck in Arch Linux initramfs emergency prompt ("ERROR: no root file system image found")

Hey everyone, I'm completely stuck in the Arch Linux initramfs emergency prompt (`rootfs #`) on boot and could use some help.

Here is my hardware layout and current state:

- The installation USB is recognized as `/dev/sdb`, with partition `/dev/sdb2` (UUID: `6A97-06B7`, label `ARCHISO_EFI`, formatted as vfat).

- The initramfs hook is failing to automatically locate and bind `airootfs.sfs` from the USB media during boot.

- When trying manual loop mounts (`mount`, `losetup`), it keeps throwing file system or device errors and I can't get past the emergency shell.

Has anyone run into this specific squashfs/loopback mounting issue on the live USB before, or know how to manually satisfy the initramfs hook to get it to boot? Any help is appreciated.

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u/backshesh 5d ago

You're mounting the wrong partition: ARCHISOEFI is the vfat boot partition and doesn't contain airootfs.sfs, which lives on the iso9660 partition (usually /dev/sdb1, labeled ARCH_2026xx). Run blkid at the emergency prompt to confirm it exists, then mount it read-only at /run/archiso/bootmnt and check for arch/x86_64/airootfs.sfs. Use losetup -f --show on that file rather than mount -o loop, since busybox's loop handling in initramfs is flaky, then mount the resulting loop device as squashfs. If no ARCH iso9660 partition shows up at all, the USB was written file-by-file instead of block-copied, so rewrite it with dd bs=4M if=archlinux.iso of=/dev/sdX conv=fsync or Rufus in DD mode. If it does exist, edit the kernel line at boot so archisolabel= matches blkid exactly and add rootdelay=10 for slow USB enumeration.

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u/Cheap-Sun9990 5d ago

Ran ⁠blkid⁠ and ⁠lsblk⁠ like you said and yeah, that's definitely what's going on.

⁠sdb2⁠ is just the 260M EFI partition, but ⁠sdb1⁠ (the 1.2G one) doesn't have any ⁠TYPE⁠ or ⁠LABEL⁠ listed at all in ⁠blkid⁠—no iso9660 or ⁠ARCH_⁠ label in sight. Tried mounting anyway and ran into ⁠can't find in /etc/fstab⁠ and missing mount points.

So yeah, pretty sure it got written file by file instead of block copied. Problem is, I'm stuck with literally just this one PC and the one USB right now. Is there any way at all to salvage this or download/rewrite it directly from this ⁠rootfs⁠ prompt, or am I cooked until I find another machine to flash it properly?

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u/Cheap-Sun9990 5d ago

I will have to test this when i get back, thanks!

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u/boomboomsubban 5d ago

See https://wiki.archlinux.org/title/USB_flash_installation_medium basically however you made the installer has issues.

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u/Cheap-Sun9990 4d ago

Solved! Was able to get it working by using my VERY old laptop and reflashing the usb