diff --git a/tests/ussd/Makefile.am b/tests/ussd/Makefile.am
index d29506c..ef9aa49 100644
--- a/tests/ussd/Makefile.am
+++ b/tests/ussd/Makefile.am
@@ -2,4 +2,4 @@
 noinst_PROGRAMS = ussd_test
 
 ussd_test_SOURCES = ussd_test.c
-ussd_test_LDADD = $(top_builddir)/src/libosmocore.la
+ussd_test_LDADD = $(top_builddir)/src/libosmocore.la $(top_builddir)/src/gsm/libosmogsm.la