diff --git a/scripts/install_build_deps.sh b/scripts/install_build_deps.sh
index 60ffb316b..b35ad7c42 100755
--- a/scripts/install_build_deps.sh
+++ b/scripts/install_build_deps.sh
@@ -52,7 +52,7 @@ fi
 
 if [ ! -z "$install" ] ; then
     if opam list --installed tezos-deps ; then
-	opam upgrade $(shell opam list -s --required-by tezos-deps)
+	opam upgrade $(opam list -s --required-by tezos-deps | grep -ve '^ocaml *$')
     else
 	opam install tezos-deps
     fi