diff --git a/pxe/install-pxe.sh b/pxe/install-pxe.sh
index 96ac03d..811240d 100755
--- a/pxe/install-pxe.sh
+++ b/pxe/install-pxe.sh
@@ -26,7 +26,7 @@ install_nfs() {
 
         # debian live nfs path is readonly, do a trick
         #   to make snapshots subdir readwrite
-        if grep -q "/snapshots" /proc/mounts; then
+        if ! grep -q "/snapshots" /proc/mounts; then
                 mount --bind "${nfs_path}/snapshots" "/snapshots"
         fi