diff --git a/utils/dockerbuilds/steamrt/start.sh b/utils/dockerbuilds/steamrt/start.sh
index d0b4ee84742..14db38a4be4 100755
--- a/utils/dockerbuilds/steamrt/start.sh
+++ b/utils/dockerbuilds/steamrt/start.sh
@@ -1,5 +1,5 @@
-#!/bin/bash
-GAMEDIR=$(cd "${0%/*}" && echo $PWD)
-cd "$GAMEDIR"
-export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$GAMEDIR/lib64"
+#!/bin/sh
+gamedir=${0%/*}
+cd "$gamedir" || exit
+export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$gamedir/lib64"
 exec ./wesnoth "$@"