diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 877dca2..f2fc982 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -9,7 +9,7 @@ jobs:
         with:
           platforms: |
             - name: "adafruit:samd"
-            - source-url: https://adafruit.github.io/arduino-board-index/package_adafruit_index.json
+            - source-url: "https://adafruit.github.io/arduino-board-index/package_adafruit_index.json"
           sketch-paths: |
             - ./
           libraries: |