📖 ~1 min read
Table of contents
Symptom & Impact
System stops at grub rescue and cannot load the kernel, causing full host downtime.
Environment & Reproduction
Can occur after partition table changes, failed disk migration, or interrupted grub updates.
Root Cause Analysis
GRUB points to invalid disk identifiers or missing core modules after storage layout changes.
Quick Triage
Confirm boot mode (UEFI/BIOS), detect root partition, and mount target system from live media.
Step-by-Step Diagnosis
Run: lsblk -o NAME,FSTYPE,UUID,MOUNTPOINT; sudo fdisk -l; sudo mount /dev/ /mnt; sudo cat /mnt/etc/fstab.
Solution – Primary Fix
Run in chroot: sudo grub-install /dev/; sudo update-grub; ensure /boot and EFI partition are mounted correctly before reboot.
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Solution – Alternative Approaches
Use Boot-Repair or restore from recent VM snapshot when manual bootloader repair is too slow.
Verification & Acceptance Criteria
GRUB menu appears and host boots to Debian 12 without manual intervention.
Rollback Plan
Revert to previous disk mapping or attach original boot disk if new boot target fails.
Prevention & Hardening
Document disk UUID changes and rerun grub-install after storage modifications.
Related Errors & Cross-Refs
Related to no such partition, missing normal.mod, and EFI boot entry corruption.
Related tutorial: View the step-by-step tutorial for debian-12.
View all debian-12 tutorials on the Tutorials Hub →
Browse all common problems & solutions on the Tutorials Hub.
References & Further Reading
GRUB manual and Debian bootloader recovery wiki guidance.
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