diff --git a/.github/workflows/retro-sbom.yml b/.github/workflows/retro-sbom.yml
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+# One-off: a CycloneDX SBOM for the already-published 1.5.0 release.
+#
+# The 1.5.0 release run's build logs are no longer available, so this reproduces the release
+# builds: rodbus 1.5.0 with the release's exact arguments, on the same hosts, recording the
+# build log and the two `cargo tree` outputs of each build. The crate set is fixed by the tag's
+# Cargo.lock, the features and the targets, so it matches the shipped binaries.
+name: Retroactive SBOM (1.5.0)
+on:
+  pull_request:
+permissions:
+  contents: read
+env:
+  RODBUS_REF: "1.5.0"
+  # rodbus with the allowed.json migrated for bom-tools 0.3.0 (stepfunc/rodbus#201)
+  CONFIG_COMMIT: e213fea869c48ce7c3972230e4c79f42dd449aa2
+jobs:
+  evidence:
+    env:
+      # as in the release build: MUSL cdylibs link MUSL libc dynamically
+      CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_RUSTFLAGS: "-C target-feature=-crt-static"
+      CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_RUSTFLAGS: "-C target-feature=-crt-static"
+      CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_RUSTFLAGS: "-C target-feature=-crt-static"
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { runner: windows-latest, build: cargo, target: x86_64-pc-windows-msvc }
+          - { runner: ubuntu-latest, build: cross, target: arm-unknown-linux-gnueabihf }
+          - { runner: ubuntu-latest, build: cross, target: aarch64-unknown-linux-gnu }
+          - { runner: ubuntu-latest, build: cross, target: x86_64-unknown-linux-gnu }
+          - { runner: ubuntu-latest, build: cross, target: aarch64-unknown-linux-musl }
+          - { runner: ubuntu-latest, build: cross, target: x86_64-unknown-linux-musl }
+          - { runner: ubuntu-latest, build: cross, target: arm-unknown-linux-musleabihf }
+    runs-on: ${{ matrix.runner }}
+    steps:
+      - name: Checkout rodbus
+        uses: actions/checkout@v6
+        with:
+          repository: stepfunc/rodbus
+          ref: ${{ env.RODBUS_REF }}
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: ${{ matrix.target }}
+      - name: Install Rust Cross
+        if: matrix.build == 'cross'
+        run: cargo install cross
+      - name: Build and record the evidence with the release's arguments
+        shell: bash
+        run: |
+          out=evidence/ffi/${{ matrix.target }}
+          mkdir -p $out
+          args=(-p rodbus-ffi --target ${{ matrix.target }} --no-default-features --features tls --locked)
+          format=(--prefix depth --color never --format '{p}|{f}')
+          ${{ matrix.build }} build --release "${args[@]}"
+          ${{ matrix.build }} build --release "${args[@]}" --message-format json > $out/build.json
+          cargo tree "${args[@]}" -e normal,build "${format[@]}" > $out/tree.txt
+          cargo tree "${args[@]}" -e normal,no-proc-macro "${format[@]}" > $out/runtime-tree.txt
+      - name: Upload the evidence
+        uses: actions/upload-artifact@v6
+        with:
+          name: evidence-${{ matrix.target }}
+          path: evidence
+  sbom:
+    needs: [evidence]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout rodbus
+        uses: actions/checkout@v6
+        with:
+          repository: stepfunc/rodbus
+          ref: ${{ env.RODBUS_REF }}
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+      - name: Download the evidence
+        uses: actions/download-artifact@v7
+        with:
+          pattern: evidence-*
+          path: evidence
+          merge-multiple: true
+      - name: Install bom-tools
+        run: cargo install --locked --git https://github.com/stepfunc/bom-tools.git --tag 0.3.0
+      - name: Create the SBOM
+        run: |
+          ls evidence/ffi/*/build.json | wc -l | grep -qx 7
+          curl -sSfL "https://raw.githubusercontent.com/stepfunc/rodbus/$CONFIG_COMMIT/allowed.json" -o reviewed-allowed.json
+          cargo metadata --format-version 1 --all-features --locked > metadata.json
+          COMMON="--root-package rodbus-ffi -m metadata.json -c reviewed-allowed.json"
+          mkdir out
+          bom-tools licenses -e evidence/ffi $COMMON > out/third-party-licenses.txt
+          bom-tools sbom -e evidence/ffi $COMMON --lockfile Cargo.lock > out/rodbus-ffi.cdx.json
+      - name: Upload the SBOM
+        uses: actions/upload-artifact@v6
+        with:
+          name: retro-sbom-1.5.0
+          path: out