Ubuntu 24.04 LTS – secure boot blocks unsigned kernel module loading

📖 ~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

Required module fails to load, disabling dependent hardware or services.

Environment & Reproduction

Occurs after kernel or driver updates on Secure Boot enabled systems.

mokutil --sb-state
modprobe 

Root Cause Analysis

Unsigned or improperly signed module is rejected by Secure Boot policy.

Quick Triage

Confirm signature-related kernel log entries.

dmesg | grep -i -E 'secure boot|module verification|lockdown'

Step-by-Step Diagnosis

Inspect module signer metadata and MOK enrollment state.

modinfo  | grep -E 'signer|sig_id|sig_key'
mokutil --list-enrolled

Solution – Primary Fix

Sign the module with an enrolled MOK key and reload it.

sudo /usr/src/linux-headers-$(uname -r)/scripts/sign-file sha256 /root/MOK.priv /root/MOK.der $(modinfo -n )
sudo modprobe 

Solution – Alternative Approaches

Use Ubuntu-signed modules from official repositories where available.

apt-cache policy 

Verification & Acceptance Criteria

Module loads without verification errors and dependent service starts.

lsmod | grep 
dmesg | tail -n 50

Rollback Plan

Revert to previously working signed module package if custom signing fails.

sudo apt-get install --reinstall 

Prevention & Hardening

Integrate module signing into DKMS pipeline for Secure Boot hosts.

Automate patch management and compliance across your fleet with our DevOps services.

dkms status

Related Errors & Cross-Refs

Related to key rejected by service and module verification failed messages.

Related tutorial: View the step-by-step tutorial for Ubuntu 24.04 LTS.

View all Ubuntu 24.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Ubuntu Secure Boot and MOK enrollment documentation.