diff --git a/.github/workflows/build-iso.yml b/.github/workflows/build-iso.yml
index 6e64457..99da23f 100644
--- a/.github/workflows/build-iso.yml
+++ b/.github/workflows/build-iso.yml
@@ -10,6 +10,8 @@ on:
       - 'assets/**'
       - 'build/**'
       - '.github/workflows/build-iso.yml'
+    tags:
+      - 'v*.*.*'
   workflow_dispatch:
     inputs:
       releasever:
@@ -24,6 +26,8 @@ jobs:
     name: Build live ISO
     runs-on: ubuntu-24.04
     timeout-minutes: 90
+    permissions:
+      contents: write
 
     steps:
       - name: Checkout
@@ -52,7 +56,9 @@ jobs:
             # core problem). CI runners always start fresh, no version skew.
             dnf -y upgrade --refresh
 
-            # Install build tooling
+            # Install build tooling. sbsigntools provides sbsign for EFI
+            # binary signing; pesign is the alternate path. xorriso is
+            # required for ISO repack after EFI signing.
             dnf -y install \
               lorax \
               livecd-tools \
@@ -64,7 +70,11 @@ jobs:
               createrepo_c \
               git \
               which \
-              shadow-utils
+              shadow-utils \
+              sbsigntools \
+              openssl \
+              dosfstools \
+              mtools
 
             cd /work
 
@@ -105,8 +115,16 @@ jobs:
             # Move output ISO to expected dir
             mv ./veilor-os-43.iso build/out/ 2>/dev/null || mv ./*.iso build/out/ 2>/dev/null || true
 
-            # Rename + checksum
-            ISO_NAME="veilor-os-${{ github.event.inputs.releasever || '43' }}-$(date +%Y%m%d-%H%M%S).iso"
+            # Rename. For tag builds use the tag as the version stamp so
+            # release artifacts have a stable, predictable name. For
+            # branch / dispatch builds use a timestamp.
+            REF_NAME="${{ github.ref_name }}"
+            if [[ "${{ github.ref_type }}" == "tag" ]]; then
+              VERSION_TAG="$REF_NAME"
+            else
+              VERSION_TAG="$(date +%Y%m%d-%H%M%S)"
+            fi
+            ISO_NAME="veilor-os-${{ github.event.inputs.releasever || '43' }}-${VERSION_TAG}.iso"
             cd build/out
             for f in *.iso; do
               [[ -f $f && $f != $ISO_NAME ]] && mv "$f" "$ISO_NAME"
@@ -114,6 +132,95 @@ jobs:
             sha256sum "$ISO_NAME" > "$ISO_NAME.sha256"
             ls -lh "$ISO_NAME"
 
+            # Stash final ISO name for later steps that run *outside* the
+            # container (signing, splitting, release). The runner sees
+            # /work/build/out, host sees ${{ github.workspace }}/build/out.
+            echo "$ISO_NAME" > /work/build/out/.iso-name
+
+      - name: Resolve ISO filename
+        id: iso
+        run: |
+          ISO_NAME=$(cat build/out/.iso-name)
+          echo "name=$ISO_NAME" >> "$GITHUB_OUTPUT"
+          echo "path=build/out/$ISO_NAME" >> "$GITHUB_OUTPUT"
+          echo "[INFO] ISO resolved: $ISO_NAME"
+
+      # ─── EFI signing (Secure Boot) ──────────────────────────────────────
+      # Only runs if MOK_PRIVATE_KEY + MOK_CERT secrets are present.
+      # Repacks the ISO in-place with sbsign'd BOOTX64.EFI / grubx64.efi.
+      # Without the secrets, ISO is shipped unsigned (testing builds).
+      - name: Sign EFI binaries (if MOK secrets present)
+        id: sbsign
+        env:
+          MOK_PRIVATE_KEY: ${{ secrets.MOK_PRIVATE_KEY }}
+          MOK_CERT: ${{ secrets.MOK_CERT }}
+        run: |
+          set -euo pipefail
+          if [[ -z "${MOK_PRIVATE_KEY:-}" || -z "${MOK_CERT:-}" ]]; then
+            echo "::warning::[INFO] MOK secrets absent — ISO unsigned for testing"
+            echo "signed=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          sudo apt-get update
+          sudo apt-get install -y sbsigntool xorriso mtools dosfstools
+
+          # Materialise key + cert from secrets to a tmp dir wiped on exit.
+          KEYDIR=$(mktemp -d)
+          trap 'rm -rf "$KEYDIR"' EXIT
+          printf '%s' "$MOK_PRIVATE_KEY" > "$KEYDIR/MOK.priv"
+          printf '%s' "$MOK_CERT" | base64 -d > "$KEYDIR/MOK.der" 2>/dev/null \
+            || printf '%s' "$MOK_CERT" > "$KEYDIR/MOK.der"
+          # sbsign prefers PEM cert input — derive on the fly.
+          openssl x509 -inform DER -in "$KEYDIR/MOK.der" -outform PEM -out "$KEYDIR/MOK.pem" \
+            || cp "$KEYDIR/MOK.der" "$KEYDIR/MOK.pem"
+          chmod 600 "$KEYDIR/MOK.priv"
+
+          ISO_PATH="${{ steps.iso.outputs.path }}"
+          WORKDIR=$(mktemp -d)
+          trap 'rm -rf "$KEYDIR" "$WORKDIR"' EXIT
+
+          # Extract EFI ESP image from ISO. xorriso prints embedded image
+          # locations; we pull the EFI/BOOT directory contents into a
+          # writable scratch dir, sign each .efi, and graft back in.
+          mkdir -p "$WORKDIR/iso-extract"
+          xorriso -osirrox on -indev "$ISO_PATH" \
+            -extract /EFI "$WORKDIR/iso-extract/EFI" 2>&1 | tail -20
+
+          SIGNED_ANY=0
+          for efi in $(find "$WORKDIR/iso-extract/EFI" -type f -iname '*.efi' 2>/dev/null); do
+            echo "[*] Signing $efi"
+            sbsign \
+              --key "$KEYDIR/MOK.priv" \
+              --cert "$KEYDIR/MOK.pem" \
+              --output "${efi}.signed" \
+              "$efi"
+            mv "${efi}.signed" "$efi"
+            SIGNED_ANY=1
+          done
+
+          if [[ $SIGNED_ANY -eq 0 ]]; then
+            echo "::warning::No EFI binaries found in ISO — skipping repack"
+            echo "signed=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          # Repack: graft the signed EFI tree back into the ISO. Use
+          # xorriso's update mode so other ISO contents (squashfs, isolinux)
+          # remain untouched.
+          xorriso \
+            -indev "$ISO_PATH" \
+            -outdev "${ISO_PATH}.signed" \
+            -boot_image any keep \
+            -map "$WORKDIR/iso-extract/EFI" /EFI \
+            -commit
+          mv "${ISO_PATH}.signed" "$ISO_PATH"
+
+          # Refresh sha256 — content changed.
+          (cd build/out && sha256sum "${{ steps.iso.outputs.name }}" > "${{ steps.iso.outputs.name }}.sha256")
+          echo "[OK] EFI binaries signed; ISO repacked + checksum refreshed."
+          echo "signed=true" >> "$GITHUB_OUTPUT"
+
       - name: Upload ISO artifact
         if: success()
         uses: actions/upload-artifact@v4
@@ -133,7 +240,102 @@ jobs:
             build/out/build.log
             build/out/build/anaconda/
 
-      - name: Attach to release
+      # ─── Release artefact pipeline ──────────────────────────────────────
+      # Triggered on tag push (v*.*.*). The 2.86 GB ISO exceeds GitHub's
+      # 2 GB single-asset cap, so we split into 1.9 GB parts and let users
+      # reassemble with `cat`. Checksum is GPG-signed so users can verify
+      # the assembled ISO end-to-end.
+      - name: Split ISO for release
+        if: github.event_name == 'push' && github.ref_type == 'tag'
+        id: split
+        run: |
+          set -euo pipefail
+          cd build/out
+          ISO="${{ steps.iso.outputs.name }}"
+          # 1900M keeps each part safely below GitHub's 2 GB asset limit
+          # (limit is 2 GiB = 2147483648 bytes; 1900 MiB = 1992294400).
+          split -b 1900M -d -a 2 "$ISO" "${ISO}.part-"
+          # Rename suffix to letter form so it matches the documented
+          # convention .part-aa, .part-ab. -d uses 00/01; we want aa/ab
+          # to make the cat glob unambiguous (no leading zero confusion).
+          mv "${ISO}.part-00" "${ISO}.part-aa"
+          mv "${ISO}.part-01" "${ISO}.part-ab" 2>/dev/null || true
+          # In rare 3-part case (>3.8 GB ISO), handle .part-02 → .part-ac
+          [[ -f "${ISO}.part-02" ]] && mv "${ISO}.part-02" "${ISO}.part-ac" || true
+          ls -lh "${ISO}".part-*
+          echo "iso=$ISO" >> "$GITHUB_OUTPUT"
+
+      - name: GPG-sign sha256 checksum
+        if: github.event_name == 'push' && github.ref_type == 'tag'
+        env:
+          GPG_PRIVATE_KEY: ${{ secrets.GPG_PRIVATE_KEY }}
+        run: |
+          set -euo pipefail
+          if [[ -z "${GPG_PRIVATE_KEY:-}" ]]; then
+            echo "::warning::GPG_PRIVATE_KEY secret missing — checksum will not be signed"
+            exit 0
+          fi
+          GNUPGHOME=$(mktemp -d)
+          export GNUPGHOME
+          chmod 700 "$GNUPGHOME"
+          # Trust the imported key automatically — CI is non-interactive.
+          printf '%s' "$GPG_PRIVATE_KEY" | gpg --batch --import
+          KEYID=$(gpg --list-secret-keys --with-colons | awk -F: '/^sec:/ {print $5; exit}')
+          echo "[*] Signing with key $KEYID"
+          cd build/out
+          ISO="${{ steps.iso.outputs.name }}"
+          gpg --batch --yes --pinentry-mode loopback \
+              --local-user "$KEYID" \
+              --armor --detach-sign \
+              --output "${ISO}.sha256.asc" \
+              "${ISO}.sha256"
+          ls -lh "${ISO}.sha256" "${ISO}.sha256.asc"
+
+      - name: Create release and attach assets
+        if: github.event_name == 'push' && github.ref_type == 'tag'
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: ${{ github.ref_name }}
+          name: veilor-os ${{ github.ref_name }}
+          draft: false
+          prerelease: false
+          generate_release_notes: true
+          fail_on_unmatched_files: false
+          files: |
+            build/out/*.iso.part-*
+            build/out/*.iso.sha256
+            build/out/*.iso.sha256.asc
+          body: |
+            ## veilor-os ${{ github.ref_name }}
+
+            ISO is split into 1.9 GB parts to fit within GitHub's 2 GB
+            per-asset upload cap. Reassemble after download:
+
+            ```bash
+            cat ${{ steps.iso.outputs.name }}.part-* > ${{ steps.iso.outputs.name }}
+            sha256sum -c ${{ steps.iso.outputs.name }}.sha256
+            ```
+
+            ### Verifying the checksum signature
+
+            ```bash
+            # Import the veilor-os release signing key (one-time):
+            gpg --keyserver keys.openpgp.org --recv-keys <KEY-ID-FROM-RELEASE-NOTES>
+
+            # Verify:
+            gpg --verify ${{ steps.iso.outputs.name }}.sha256.asc \
+                        ${{ steps.iso.outputs.name }}.sha256
+            ```
+
+            ### Secure Boot
+
+            EFI binaries are signed with the veilor-os MOK if signing
+            secrets were configured at build time. To enroll the public
+            cert post-install, see `scripts/gen-mok-key.sh` header.
+
+      # Legacy hook: keeps the manual `release.published` workflow path
+      # working. Tag-driven flow above is the new canonical entry point.
+      - name: Attach to release (legacy release event)
         if: github.event_name == 'release'
         uses: softprops/action-gh-release@v2
         with:
diff --git a/.github/workflows/release-checksums.yml b/.github/workflows/release-checksums.yml
new file mode 100644
index 0000000..89ba776
--- /dev/null
+++ b/.github/workflows/release-checksums.yml
@@ -0,0 +1,100 @@
+name: Release Checksums
+
+# PR-time validation gate for release-affecting files. Independent of
+# lint.yml — meant to harden the brittle parts (ksvalidator on the
+# generated CI kickstart, shellcheck across all maintained scripts,
+# YAML sanity on every workflow).
+#
+# This workflow does NOT replace lint.yml; it runs alongside.
+
+on:
+  pull_request:
+    paths:
+      - 'kickstart/**'
+      - 'scripts/**'
+      - '.github/workflows/**'
+  push:
+    branches: [main]
+    paths:
+      - 'kickstart/**'
+      - 'scripts/**'
+      - '.github/workflows/**'
+
+jobs:
+  ksvalidate:
+    name: ksvalidator (CI-flavour kickstart)
+    runs-on: ubuntu-24.04
+    container:
+      image: registry.fedoraproject.org/fedora:43
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install pykickstart
+        run: dnf -y install pykickstart sed
+
+      - name: Generate CI kickstart and validate
+        run: |
+          set -euxo pipefail
+          # Mirror what build-iso.yml does so we're validating the file
+          # the actual builder consumes, not just the source kickstart.
+          sed -e '/veilor-fix/d' \
+              -e '/^shutdown$/d' \
+              kickstart/veilor-os.ks > kickstart/veilor-os-ci.ks
+          ksvalidator kickstart/veilor-os.ks
+          ksvalidator kickstart/veilor-os-ci.ks
+
+  shellcheck:
+    name: shellcheck (release scripts)
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: shellcheck repo scripts
+        uses: ludeeus/action-shellcheck@master
+        with:
+          severity: warning
+          # Same exclusions as lint.yml so behaviour is consistent.
+          ignore_paths: build/cache .github
+
+  workflow-yaml:
+    name: workflow YAML sanity
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+      - name: Validate every workflow parses as YAML
+        run: |
+          set -euo pipefail
+          python3 - <<'PY'
+          import sys, pathlib, yaml
+          ok = True
+          for p in pathlib.Path(".github/workflows").glob("*.y*ml"):
+              try:
+                  yaml.safe_load(p.read_text())
+                  print(f"[OK] {p}")
+              except yaml.YAMLError as e:
+                  print(f"[ERR] {p}: {e}", file=sys.stderr)
+                  ok = False
+          sys.exit(0 if ok else 1)
+          PY
+
+  release-asset-budget:
+    name: Release asset size budget
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+      - name: Confirm split threshold is below GitHub's 2 GiB asset cap
+        run: |
+          set -euo pipefail
+          # GitHub per-asset upload limit is 2 GiB = 2147483648 bytes.
+          # split is invoked with -b 1900M = 1900 * 2^20 = 1992294400 bytes.
+          # Hard-fail if anyone bumps the split size beyond the cap.
+          if grep -E 'split -b [0-9]+M' .github/workflows/build-iso.yml >/dev/null; then
+            SIZE_M=$(grep -oE 'split -b [0-9]+M' .github/workflows/build-iso.yml | head -1 | grep -oE '[0-9]+')
+            if [[ "$SIZE_M" -gt 2047 ]]; then
+              echo "::error::split -b ${SIZE_M}M exceeds GitHub's 2 GiB per-asset cap"
+              exit 1
+            fi
+            echo "[OK] split size ${SIZE_M}M is under the 2 GiB asset limit."
+          else
+            echo "::warning::No split -b NM directive found — release pipeline may have changed"
+          fi
diff --git a/.gitignore b/.gitignore
index 6679260..2853d6d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 build/out/
 build/cache/
+build/keys/
 *.iso
 *.img
 *.log
@@ -11,5 +12,7 @@ build/cache/
 secrets/
 *.key
 *.pem
+*.priv
+*.der
 test/veilor-vm.qcow2
 test/veilor-vm.nvram*
diff --git a/scripts/gen-mok-key.sh b/scripts/gen-mok-key.sh
new file mode 100755
index 0000000..b338bfc
--- /dev/null
+++ b/scripts/gen-mok-key.sh
@@ -0,0 +1,94 @@
+#!/usr/bin/env bash
+# gen-mok-key.sh — Generate a Machine Owner Key (MOK) pair for Secure Boot
+#
+# Purpose:
+#   Produces an RSA-4096 key pair used to sign EFI binaries (BOOTX64.EFI,
+#   shim, grub) and out-of-tree kernel modules so they pass UEFI Secure Boot
+#   verification once the public cert is enrolled in the firmware.
+#
+# Output (gitignored):
+#   build/keys/MOK.priv  — PEM private key (sbsign / sign-file input)
+#   build/keys/MOK.der   — DER public certificate (mokutil enrollment input)
+#   build/keys/MOK.pem   — PEM public certificate (sbsign --cert input)
+#
+# Idempotent: if MOK.priv already exists, exits 0 without regenerating.
+# Re-running with existing keys is safe — won't clobber a key already used
+# to sign released ISOs.
+#
+# ─── User enrollment workflow (post-install) ─────────────────────────────
+#   1. Copy build/keys/MOK.der to the installed system (USB / scp / etc.)
+#   2. On the booted veilor-os system, as root:
+#          mokutil --import /path/to/MOK.der
+#      Set a one-time password when prompted.
+#   3. Reboot. The shim's MokManager will appear on next boot — choose
+#      "Enroll MOK", confirm with the password from step 2, then continue
+#      boot. The cert is now in the kernel's .platform keyring.
+#   4. Verify enrollment:
+#          mokutil --list-enrolled | grep -A2 'veilor'
+#
+# ─── Uploading to GitHub Actions secrets ─────────────────────────────────
+# After running this script, populate the CI signing secrets with:
+#     gh secret set MOK_PRIVATE_KEY < build/keys/MOK.priv
+#     gh secret set MOK_CERT        < build/keys/MOK.der
+#
+# Keep build/keys/ off-disk-backup-medium-of-record offline. Anyone with
+# MOK.priv can sign code that boots on enrolled machines.
+#
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+KEY_DIR="$REPO_ROOT/build/keys"
+
+PRIV_KEY="$KEY_DIR/MOK.priv"
+DER_CERT="$KEY_DIR/MOK.der"
+PEM_CERT="$KEY_DIR/MOK.pem"
+
+# Subject for the X.509 cert. Tweak CN if you fork the project.
+SUBJ="/CN=veilor-os Machine Owner Key/O=veilor-org/OU=secure-boot/"
+
+# Cert validity — 10 years. Long enough that we don't churn re-enrollment;
+# short enough that a leaked key has a hard expiry.
+DAYS=3650
+
+if [[ -f "$PRIV_KEY" ]]; then
+  echo "[INFO] $PRIV_KEY already exists — skipping (idempotent)."
+  echo "[INFO] To regenerate, delete $KEY_DIR/ first."
+  exit 0
+fi
+
+mkdir -p "$KEY_DIR"
+chmod 700 "$KEY_DIR"
+
+echo "[*] Generating RSA-4096 MOK keypair → $KEY_DIR/"
+
+# Single openssl invocation produces PEM private key + DER public cert.
+# -nodes = no passphrase on the key (CI must use it non-interactively).
+# Protect the resulting MOK.priv with filesystem perms only.
+openssl req \
+  -new \
+  -x509 \
+  -newkey rsa:4096 \
+  -nodes \
+  -sha256 \
+  -days "$DAYS" \
+  -subj "$SUBJ" \
+  -keyout "$PRIV_KEY" \
+  -outform DER \
+  -out "$DER_CERT"
+
+# Also emit a PEM-encoded copy of the cert — sbsign accepts PEM more
+# reliably than DER in some distros' build of the tool.
+openssl x509 -inform DER -in "$DER_CERT" -outform PEM -out "$PEM_CERT"
+
+chmod 600 "$PRIV_KEY"
+chmod 644 "$DER_CERT" "$PEM_CERT"
+
+echo "[OK] MOK keypair written:"
+echo "      private : $PRIV_KEY  (mode 600)"
+echo "      cert DER: $DER_CERT  (enroll via mokutil --import)"
+echo "      cert PEM: $PEM_CERT  (sbsign --cert input)"
+echo ""
+echo "[next] Upload to CI:"
+echo "      gh secret set MOK_PRIVATE_KEY < $PRIV_KEY"
+echo "      gh secret set MOK_CERT        < $DER_CERT"