diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index da0ceae..69eee65 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -31,7 +31,7 @@ jobs:
       run: |
         arduino-cli config init
         arduino-cli config add board_manager.additional_urls https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json
-        arduino-cli core install rp2040:rp2040
+        arduino-cli core install rp2040:rp2040@3.9.5
       shell: bash
     - name: Install Arduino Libraries
       run: |