📖 ~1 min read
Table of contents
Symptom & Impact
System fails to boot after kernel updates, causing service outage.
Environment & Reproduction
Observed on systems with dual disks, EFI changes, or interrupted postinst scripts.
Root Cause Analysis
GRUB modules or bootloader installation target became inconsistent with current disk layout.
Quick Triage
Boot an older kernel entry if available and gather bootloader state.
Step-by-Step Diagnosis
Validate EFI partition mounts and GRUB config generation output.
Solution – Primary Fix
Reinstall GRUB to the correct target and regenerate configuration.
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Solution – Alternative Approaches
From rescue media, chroot and reinstall kernel and GRUB packages.
Verification & Acceptance Criteria
Host boots normally and latest kernel loads successfully.
Rollback Plan
Set a known-good previous kernel as default while investigating hardware/firmware issues.
Prevention & Hardening
Keep boot partitions healthy and test kernel upgrades on canary hosts first.
Related Errors & Cross-Refs
grub rescue>, unknown filesystem, no such partition.
Related tutorial: View the step-by-step tutorial for Debian 13.
View all Debian 13 tutorials on the Tutorials Hub →
Browse all common problems & solutions on the Tutorials Hub.
References & Further Reading
Debian GRUB and kernel upgrade troubleshooting documentation.
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