Debian 9 – kernel or grub updates fail because /boot is full

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Kernel package and grub operations fail, increasing reboot risk after patching.

Environment & Reproduction

Most common on small dedicated /boot partitions retaining many kernels.

# Capture baseline
df -h /boot
dpkg -l | grep linux-image
uname -r
ls -lh /boot

Root Cause Analysis

Insufficient free space prevents initramfs and grub artifacts from being generated.

Quick Triage

Determine active kernel and list removable historical kernels safely.

# Quick triage
uname -r
dpkg -l | grep -E linux-image|linux-headers
apt-get -s autoremove | sed -n 1,80p

Step-by-Step Diagnosis

Correlate package failures with /boot usage and generated artifact counts.

# Detailed diagnosis
apt-get -f install 2>&1 | tee /tmp/boot_full_157.log
awk /No space left/ /tmp/boot_full_157.log
du -sh /boot/* | sort -h

Solution – Primary Fix

Remove old kernels, then regenerate initramfs and update grub.

# Primary fix
sudo apt-get autoremove --purge
sudo update-initramfs -u -k all
sudo update-grub

Solution – Alternative Approaches

Expand /boot where possible or tune kernel retention policy.

# Alternatives
sudo dpkg -l | grep linux-image
sudo apt-get remove --purge linux-image-

Verification & Acceptance Criteria

Kernel packages configure successfully and grub update completes with no space errors.

# Verify
df -h /boot
sudo dpkg --configure -a
sudo update-grub

Rollback Plan

Reinstall required kernel packages if cleanup removed needed images.

# Rollback
sudo apt-get install linux-image- linux-headers-

Prevention & Hardening

Implement regular kernel cleanup and monitor /boot utilization.

# Hardening
apt-get -s autoremove
df -h /boot

Related Errors & Cross-Refs

Related messages include No space left on device and update-initramfs failures.

Related tutorial: View the step-by-step tutorial for Debian 9.

View all Debian 9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Debian kernel package lifecycle and grub maintenance documentation.