secure-boot-cert-rotation SKILL.md skillA
secure-boot-cert-rotation from air-gapped/skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add air-gapped/skills/secure-boot-cert-rotation@git:20261027.ee804fePins git:20261027.ee804fe in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- air-gapped/skills
- Path
.claude/skills/secure-boot-cert-rotation/SKILL.md- Versions recorded
- 8
- Latest version
- git:20261027.1ddfb13, committed Oct 27, 2026
- First version recorded
- Aug 17, 2026
- Size
- 12,817 bytes
- Repository stars
- 6
- License
- MIT
Triage and fix the Microsoft Secure Boot 2011→2023 UEFI certificate rotation across Dell PowerEdge / iDRAC9 bare metal, Ubuntu/Linux servers, and Harvester HCI / KubeVirt guest VMs. Two 2011 CAs expired June 2026 and Windows Production PCA 2011 expires 2026-10-19 — but UEFI firmware ignores certificate expiry, so nothing stopped booting; the real risks are forward-compat once a 2023-only-signed shim arrives (already true on aarch64) plus a dbx/revocation freeze. Routes to the per-platform fix…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# secure-boot-cert-rotation Triage and fix the **Microsoft Secure Boot 2011→2023 certificate rotation** on a real, mixed fleet. Microsoft's original 2011 Secure Boot CAs expire in 2026; their 2023 replacements take over. This skill exists to stop the two failure modes operators actually hit: (1) **panic** — believing servers will stop booting on the expiry date (they won't), and (2) **applying the wrong tool** — reaching for `fwupd`/LVFS on hardware and VMs it cannot serve, instead of the firmware-native path. The work is almost never the cert write itself — it's **knowing which of three firmware surfaces a given machine has** (Dell host firmware, generic Linux host firmware, or a VM's virtual OVMF varstore), because each is updated by a different mechanism and `fwupd` only covers one of them. ## The one load-bearing fact — read this before anything else **UEFI firmware does not check a certificate's expiry date when validating Secure Boot signatures.** EDK2 sets `NO_CHECK_TIME` on PKCS#7 verification on purpose (there is no trustworthy clock at boot; enforcing `notAfter` would be a self-inflicted brick vector). Canonical, Red Hat, fwupd, and LWN all state this independently. …
Read the whole file at its exact version.
How to install
mdr add air-gapped/skills/secure-boot-cert-rotation@sha256:7117779db5acfa8aThe line at the top of this page pins the label git:20261027.ee804fe, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_nfe25nyzmqsexeln)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 8 versions of this file, between Aug 17, 2026 and Oct 27, 2026, about one every 10 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261027.1ddfb13 latest | 2026-10-27 | 1ddfb13 | 12,817 B | A | view · diff |
| git:20261027.1e7bd7e | 2026-10-27 | 1e7bd7e | 12,864 B | A | view · diff |
| git:20261027.ee804fe | 2026-10-27 | ee804fe | 12,836 B | A | view · diff |
| git:20260915.3e9018e | 2026-09-15 | 3e9018e | 12,895 B | A | view · diff |
| git:20260817.66f15e8 | 2026-08-17 | 66f15e8 | 12,603 B | A | view · diff |
| git:20260817.81a3bbe | 2026-08-17 | 81a3bbe | 12,488 B | A | view · diff |
| git:20260817.dc7eef1 | 2026-08-17 | dc7eef1 | 12,478 B | A | view · diff |
| git:20260817.dd0a4b5 | 2026-08-17 | dd0a4b5 | 12,454 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (12817 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
air-gapped/skills · 6 stars · license MIT · pushed 2026-11-04 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_nfe25nyzmqsexeln GET https://markdownregistry.com/api/v1/resolve?ref=air-gapped/skills/secure-boot-cert-rotation GET https://markdownregistry.com/api/v1/blob/7117779db5acfa8a4425e1363e058673bf6e204fba9ad6ebe64bff861d2da3e1
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.