diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 98ff15c..5ff30cf 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -317,7 +317,7 @@
 #      caveat: net9 is (currently?) NOT installed, so manually again
       - name: Set up .NET SDK
         run: |
-          sudo add-apt-repository ppa:dotnet/backports
+          sudo add-apt-repository -y ppa:dotnet/backports
           sudo apt-get install -y --no-install-recommends dotnet-sdk-9.0
 #      end