diff --git a/dev-setup-git.sh b/dev-setup-git.sh
index 70845da..caffcea 100755
--- a/dev-setup-git.sh
+++ b/dev-setup-git.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-if [[ "$(git rev-parse --show-toplevel)" = "$(dirname -- "${BASH_SOURCE[0]}")" ]]; then
+if [[ "$(git rev-parse --show-toplevel 2> /dev/null)" = "$(dirname -- "${BASH_SOURCE[0]}")" ]]; then
   echo "Error: run this from a new build directory, not from within the br2-external git repo"
   exit 1
 fi