diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index b1ad6ba3..6c1f8a31 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -57,7 +57,7 @@ jobs:
         if: ${{ env.run-build == 'true' }}
         run: |
           arduino-cli core update-index ${{ format('{0}', steps.prep.outputs.index-url) }}
-          arduino-cli core install ${{ format('{0}:{1}', steps.split.outputs._0, steps.split.outputs._1) }}
+          arduino-cli core install ${{ format('{0}:{1} {2}', steps.split.outputs._0, steps.split.outputs._1, steps.prep.outputs.index-url) }}
       
       - name: Checkout repository
         if: ${{ env.run-build == 'true' }}