diff --git a/dev/ci/docker_linux/docker_push.sh b/dev/ci/docker_linux/docker_push.sh
index 094413757ee..cb3112e8bc1 100755
--- a/dev/ci/docker_linux/docker_push.sh
+++ b/dev/ci/docker_linux/docker_push.sh
@@ -2,5 +2,8 @@
 
 TAG="${CIRRUS_TAG:-latest}"
 
-sudo docker push "gcr.io/flutter-cirrus/build-flutter-image:$TAG"
+# Convert "+" to "-" to make hotfix tags legal Docker tag names.
+# See https://docs.docker.com/engine/reference/commandline/tag/
+TAG=${TAG/+/-}
 
+sudo docker push "gcr.io/flutter-cirrus/build-flutter-image:$TAG"
diff --git a/packages/flutter_tools/gradle/flutter.gradle b/packages/flutter_tools/gradle/flutter.gradle
index 173ba30c9a8..dcbf787a903 100644
--- a/packages/flutter_tools/gradle/flutter.gradle
+++ b/packages/flutter_tools/gradle/flutter.gradle
@@ -353,7 +353,7 @@ class FlutterPlugin implements Plugin<Project> {
                 return
             }
             Project dependencyProject = project.rootProject.findProject(":$pluginDependencyName")
-            if (dependencyProject == null) {
+            if (!dependencyProject.projectDir.exists() || dependencyProject == null) {
                 return
             }
             // Wait for the Android plugin to load and add the dependency to the plugin project.