diff --git a/package/gluon-core/generate/lib/gluon/upgrade/core/invariant/011-ntp-servers b/package/gluon-core/generate/lib/gluon/upgrade/core/invariant/011-ntp-servers
index fa69b0535e9c14efd73b23b32ff8fe69c2430cdb..db82e9505edf5331b302745fa52ae21fac2ef23f 100755
--- a/package/gluon-core/generate/lib/gluon/upgrade/core/invariant/011-ntp-servers
+++ b/package/gluon-core/generate/lib/gluon/upgrade/core/invariant/011-ntp-servers
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-[ -n '@ntp_servers@' ] || exit 0
+[ -n "$(echo @ntp_servers@)" ] || exit 0
 
 
 uci delete system.ntp.server