diff --git a/.gitea/workflows/self-check.yml b/.gitea/workflows/self-check.yml
index 9ca0641..6927a4e 100644
--- a/.gitea/workflows/self-check.yml
+++ b/.gitea/workflows/self-check.yml
@@ -7,6 +7,9 @@ on:
 
 jobs:
   crosscheck:
+    # Gitea dispatches a reusable-workflow call to a runner chosen by the CALLER's runs-on;
+    # without one, any runner may take it (the instance's pi5-runner did, and failed).
+    runs-on: flutter-android
     uses: yukart/tool-crosscheck/.gitea/workflows/crosscheck.yml@master
     with:
       repo: ${{ github.event.repository.name }}
diff --git a/caller/crosscheck.yml b/caller/crosscheck.yml
index 9ca0641..6927a4e 100644
--- a/caller/crosscheck.yml
+++ b/caller/crosscheck.yml
@@ -7,6 +7,9 @@ on:
 
 jobs:
   crosscheck:
+    # Gitea dispatches a reusable-workflow call to a runner chosen by the CALLER's runs-on;
+    # without one, any runner may take it (the instance's pi5-runner did, and failed).
+    runs-on: flutter-android
     uses: yukart/tool-crosscheck/.gitea/workflows/crosscheck.yml@master
     with:
       repo: ${{ github.event.repository.name }}