diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 86f8671ff635386fd1ab10e27802251fb271a422..cf684f53f51012e593fda79426aa5c5d1c926444 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -89,7 +89,7 @@ synth-check-programming-files:
 trigger-opc-ua-test:
     stage: hardware
     variables:
-        HDL_BRANCH: $CI_COMMIT_BRANCH
+        HDL_BRANCH: '$CI_COMMIT_BRANCH'
     only:
         changes:
             - applications/lofar2/images/lofar2_unb2b_sdp_station_full.tar.gz