📖 ~1 min read
Table of contents
Symptom & Impact
Security fixes are missing because host keeps booting an outdated kernel image.
Environment & Reproduction
Debian 13 systems with custom GRUB defaults or incomplete bootloader updates.
Root Cause Analysis
GRUB menu entry ordering or default settings still point to older kernel versions.
Quick Triage
Compare installed kernel packages with running kernel and GRUB default.
Step-by-Step Diagnosis
Inspect generated GRUB menu entries and bootloader update output.
Solution – Primary Fix
Set GRUB to latest kernel, regenerate config, and reboot with console access ready.
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Solution – Alternative Approaches
Use grub-set-default for explicit saved entries in controlled boot workflows.
Verification & Acceptance Criteria
After reboot, uname -r matches latest installed signed kernel package.
Rollback Plan
Boot previous kernel from GRUB advanced menu if regressions are detected.
Prevention & Hardening
Track kernel boot target in compliance checks after each patch cycle.
Related Errors & Cross-Refs
Related concerns include DKMS module mismatch and initramfs missing modules.
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 kernel handbook and GRUB administration guides.
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