diff --git a/examples/01_real-from-ideal.sh b/examples/01_real-from-ideal.sh
index 9c2870cac7dbe3ce6ded20bb090fb51fe2cdd4aa..80019afa13bab347ca13c330161677bfcaf604e8 100644
--- a/examples/01_real-from-ideal.sh
+++ b/examples/01_real-from-ideal.sh
@@ -133,7 +133,7 @@ spack:
 
 icon:
   #build_cmd: "icon-nwp@%ICON.VERSION%% %SPACK.COMPILER%+debug+petsc target=x86_64_v2 ^openmpi+pmi+legacylaunchers schedulers=slurm fabrics=ucx ucx+dc+dm+ib_hw_tm+mlx5_dv+rc+rdmacm+thread_multiple+ud+verbs"
-  build_cmd: "icon-nwp@%ICON.VERSION%% %SPACK.COMPILER%+debug target=x86_64_v2"
+  build_cmd: "icon-nwp@%ICON.VERSION%% %SPACK.COMPILER%+debug target=x86_64_v2 source=dkrz_https"
   version: psp
 
 data_management: