diff --git a/system/extras/prebuild.sh b/system/extras/prebuild.sh
index 91f878c66f..2bb4e124f6 100755
--- a/system/extras/prebuild.sh
+++ b/system/extras/prebuild.sh
@@ -1,5 +1,7 @@
 #!/bin/bash
 
+printf "%s\n" "$SHELL" 1>&2
+
 BUILD_PATH="$1"
 BUILD_SOURCE_PATH="$2"
 BOARD_PLATFORM_PATH="$3"