FreeBSD 12 bhyve VM Hangs at Boot After UEFI Update

📖 ~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

VM does not reach bootloader, causing service downtime.

Environment & Reproduction

Seen after firmware package or VM template updates.

sudo vm start 

Root Cause Analysis

Incompatible UEFI variable state or boot order breaks guest startup.

Quick Triage

Verify console output and current bhyve firmware file.

tail -n 200 /var/log/vm/.log

Step-by-Step Diagnosis

Inspect bhyve command line and guest loader vars.

ps aux | grep bhyve

Solution – Primary Fix

Reset guest UEFI vars and apply known-good firmware file.

sudo rm -f /zroot/vm//uefi-vars.fd && sudo vm start 

Solution – Alternative Approaches

Boot with legacy loader configuration for temporary recovery.

Verification & Acceptance Criteria

Guest reaches OS boot and services pass health checks.

Rollback Plan

Revert VM definition and firmware artifact to previous release.

Prevention & Hardening

Version-control VM templates and test firmware upgrades in staging.

Related Errors & Cross-Refs

Can overlap with virtio driver mismatch inside guests.

Related tutorial: View the step-by-step tutorial for freebsd-12.

View all freebsd-12 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

bhyve firmware and VM lifecycle documentation.