diff --git a/openup b/openup
index e29bf32..4dabf8b 100755
--- a/openup
+++ b/openup
@@ -76,7 +76,7 @@ unset _BPLIST
 
 _MEESA=$(readlink -f $0)
 _MEESA_ARGS="${@}"
-_TMPDIR="${_TMPDIR:=/tmp}"
+_TMPDIR="${TMPDIR:=/tmp}"
 _TMPCERT=$(mktemp -p ${_TMPDIR} openup-pkg_cert.XXXXXX) || exit 1
 _TMPSPLITCERT=$(mktemp -p ${_TMPDIR} openup-split_cert.XXXXXX) || exit 1
 _TMPUPD=$(mktemp -p ${_TMPDIR} openup-update.XXXXXX) || exit 1