🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026
Affected versions: SUSE Linux Enterprise Server 16

📖 ~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

After `snapper rollback`, the next boot still lands on the previous default snapshot.

Environment & Reproduction

Seen on UEFI SLES 16 systems where GRUB2 default entry was overridden manually.

Root Cause Analysis

`grub2-mkconfig` did not regenerate the default-subvolume entry after the rollback.

Quick Triage

Inspect `/boot/grub2/grub.cfg` and confirm the active subvolume with `btrfs subvolume get-default /`.

Step-by-Step Diagnosis

Compare `snapper list` default flag with `grub2-editenv list` saved entry.

Illustrative mockup for sles-16 — snapper_rollback-boot-fail_terminal
Terminal diagnostics for Snapper rollback selected but system boots old default — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Run `snapper rollback ` then `grub2-mkconfig -o /boot/grub2/grub.cfg` and reboot.

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Illustrative mockup for sles-16 — snapper_rollback-boot-fail_logs
Logs and evidence for Snapper rollback selected but system boots old default — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Use `transactional-update grub.cfg` on transactional systems instead of regenerating manually.

Verification & Acceptance Criteria

After reboot `snapper status` shows the chosen snapshot as default and read-write.

Rollback Plan

Re-run rollback to the prior snapshot if the new default introduces regressions.

Prevention & Hardening

Avoid manual edits to `/etc/default/grub` outside the configuration management workflow.

Often co-occurs with `efibootmgr` showing the wrong boot order.

Related tutorial: View the step-by-step tutorial for sles-16.

View all sles-16 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Snapper rollback workflow and GRUB2 integration on SLES 16.

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