diff --git a/.gitea/workflows/test.yml b/.gitea/workflows/test.yml
index 5ac0137..d705777 100644
--- a/.gitea/workflows/test.yml
+++ b/.gitea/workflows/test.yml
@@ -40,13 +40,36 @@ on:
   workflow_dispatch:
 
 jobs:
+  stage-firecracker-inputs:
+    runs-on: [self-hosted, kvm]
+    steps:
+      - name: Stage the provisioned static dropbear
+        run: |
+          mkdir -p firecracker-inputs
+          cp /var/cache/bot-bottle-fc/dropbear firecracker-inputs/dropbear
+
+      - name: Upload Firecracker build inputs
+        uses: actions/upload-artifact@v3
+        with:
+          name: firecracker-inputs
+          path: firecracker-inputs/
+
   build-infra:
+    needs: stage-firecracker-inputs
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Download Firecracker build inputs
+        uses: actions/download-artifact@v3
+        with:
+          name: firecracker-inputs
+          path: firecracker-inputs
+
       - name: Build infra candidate from this checkout
+        env:
+          BOT_BOTTLE_FC_DROPBEAR: ${{ github.workspace }}/firecracker-inputs/dropbear
         run: python3 -m bot_bottle.backend.firecracker.publish_infra --output infra-candidate
 
       - name: Upload infra candidate
diff --git a/bot_bottle/backend/firecracker/infra_artifact.py b/bot_bottle/backend/firecracker/infra_artifact.py
index 8d76846..b4f5cf6 100644
--- a/bot_bottle/backend/firecracker/infra_artifact.py
+++ b/bot_bottle/backend/firecracker/infra_artifact.py
@@ -87,6 +87,9 @@ def infra_artifact_version(init_script: str, *, repo_root: Path = _REPO_ROOT) ->
         h.update((repo_root / name).read_bytes())
     h.update(b"pyproject.toml\0")
     h.update((repo_root / "pyproject.toml").read_bytes())
+    h.update(b"dropbear\0")
+    dropbear = util.dropbear_path()
+    h.update(dropbear.read_bytes() if dropbear.is_file() else b"<missing>")
     h.update(b"init\0")
     h.update(init_script.encode())
     return h.hexdigest()[:16]
diff --git a/bot_bottle/backend/firecracker/publish_infra.py b/bot_bottle/backend/firecracker/publish_infra.py
index 495b1d1..631ec81 100644
--- a/bot_bottle/backend/firecracker/publish_infra.py
+++ b/bot_bottle/backend/firecracker/publish_infra.py
@@ -197,6 +197,7 @@ def main(argv: list[str] | None = None) -> int:
         print(f"built infra rootfs candidate {version}")
         return 0
 
+    assert args.publish_dir is not None
     version = _publish_bundle(args.publish_dir, token)
     print(f"published infra rootfs {version}")
     return 0
diff --git a/tests/unit/test_infra_artifact.py b/tests/unit/test_infra_artifact.py
index 4699354..c9dadcd 100644
--- a/tests/unit/test_infra_artifact.py
+++ b/tests/unit/test_infra_artifact.py
@@ -105,6 +105,20 @@ class TestVersionInputs(unittest.TestCase):
             after = ia.infra_artifact_version("init", repo_root=root)
         self.assertNotEqual(before, after)
 
+    def test_dropbear_change_bumps_version(self) -> None:
+        with tempfile.TemporaryDirectory() as d:
+            root = Path(d)
+            self._fake_repo(root)
+            dropbear = root / "dropbear"
+            dropbear.write_bytes(b"dropbear-v1")
+            with mock.patch.dict(os.environ, {
+                "BOT_BOTTLE_FC_DROPBEAR": str(dropbear),
+            }):
+                before = ia.infra_artifact_version("init", repo_root=root)
+                dropbear.write_bytes(b"dropbear-v2")
+                after = ia.infra_artifact_version("init", repo_root=root)
+        self.assertNotEqual(before, after)
+
     def test_non_python_file_change_bumps_version(self) -> None:
         with tempfile.TemporaryDirectory() as d:
             root = Path(d)
diff --git a/tests/unit/test_publish_infra.py b/tests/unit/test_publish_infra.py
index b257c08..fc27e8c 100644
--- a/tests/unit/test_publish_infra.py
+++ b/tests/unit/test_publish_infra.py
@@ -7,6 +7,7 @@ read it into memory. Network is mocked; no Docker, no real build.
 from __future__ import annotations
 
 import hashlib
+from email.message import Message
 import tempfile
 import unittest
 import urllib.error
@@ -88,7 +89,7 @@ class TestPublishBundle(unittest.TestCase):
         with tempfile.TemporaryDirectory() as d:
             root = Path(d)
             self._bundle(root, "v1")
-            missing = urllib.error.HTTPError("u", 404, "missing", {}, None)
+            missing = urllib.error.HTTPError("u", 404, "missing", Message(), None)
             with mock.patch.object(
                 pub.infra_artifact, "infra_artifact_version", return_value="v1"
             ), mock.patch.object(