diff --git a/host/xtest/Makefile b/host/xtest/Makefile
index af45f5e..36c7e3d 100644
--- a/host/xtest/Makefile
+++ b/host/xtest/Makefile
@@ -137,6 +137,8 @@
 CFLAGS += -I../../ta/large/include
 CFLAGS += -I../../ta/supp_plugin/include
 CFLAGS += -I../../ta/bti_test/include
+CFLAGS += -I../../ta/subkey1/include
+CFLAGS += -I../../ta/subkey2/include
 
 TA_DIR ?= /lib/optee_armtz
 CFLAGS += -DTA_DIR=\"$(TA_DIR)\"