diff --git a/.gitea/workflows/release.yml b/.gitea/workflows/release.yml
index 560ad7e..bb1c8d5 100644
--- a/.gitea/workflows/release.yml
+++ b/.gitea/workflows/release.yml
@@ -4,13 +4,27 @@ name: Release
 # to it. mod_version in gradle.properties is the source of truth: the release
 # tag must match it (a leading "v" is allowed), so bump mod_version in a PR
 # before tagging the release.
+#
+# To (re)attach jars to an existing release, run this workflow manually with
+# the release's tag.
 on:
   release:
     types: [published]
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: Tag of the existing release to build and attach jars to
+        required: true
 
 permissions:
   contents: write
 
+env:
+  TAG: ${{ github.event.release.tag_name || inputs.tag }}
+  # Gitea's internal address. Uploads bypass the Cloudflare tunnel, which
+  # rejects request bodies as large as the mod jars (413).
+  GITEA_API: http://gitea:3000/api/v1
+
 jobs:
   build:
     runs-on: ubuntu-latest
@@ -18,11 +32,10 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
         with:
+          ref: ${{ env.TAG }}
           submodules: true
 
       - name: Check tag matches mod_version
-        env:
-          TAG: ${{ github.event.release.tag_name }}
         run: |
           MOD_VERSION="$(sed -n 's/^mod_version=//p' gradle.properties | tr -d '[:space:]')"
           if [ "${TAG#v}" != "$MOD_VERSION" ]; then
@@ -47,7 +60,7 @@ jobs:
       - name: Upload jars to the release
         env:
           TOKEN: ${{ secrets.GITEA_TOKEN }}
-          ASSETS_URL: ${{ github.server_url }}/api/v1/repos/${{ github.repository }}/releases/${{ github.event.release.id }}/assets
+          REPO: ${{ github.repository }}
         run: |
           shopt -s nullglob
           jars=(build/allJars/*.jar)
@@ -56,11 +69,20 @@ jobs:
             exit 1
           fi
 
+          # Look the release up by tag so manual runs work too.
+          RELEASE_ID="$(curl --fail-with-body -sS -H "Authorization: token $TOKEN" \
+            "$GITEA_API/repos/$REPO/releases/tags/$TAG" \
+            | grep -o '"id":[0-9]*' | head -n1 | cut -d: -f2)"
+          if [ -z "$RELEASE_ID" ]; then
+            echo "No release found for tag $TAG" >&2
+            exit 1
+          fi
+
           for jar in "${jars[@]}"; do
-            echo "Uploading $(basename "$jar")"
+            echo "Uploading $(basename "$jar") to release $TAG ($RELEASE_ID)"
             curl --fail-with-body -sS -X POST \
               -H "Authorization: token $TOKEN" \
               -F "attachment=@$jar" \
-              "$ASSETS_URL"
+              "$GITEA_API/repos/$REPO/releases/$RELEASE_ID/assets"
             echo
           done