diff --git a/yotta/data/adjust-config.sh b/yotta/data/adjust-config.sh
index 170d307..6580c09 100755
--- a/yotta/data/adjust-config.sh
+++ b/yotta/data/adjust-config.sh
@@ -14,6 +14,10 @@
     $SCRIPT -f $FILE $@
 }
 
+
+# Set the target specific header
+conf set YOTTA_CFG_MBEDTLS_USER_CONFIG_FILE \"target_config.h\"
+
 # not supported on mbed OS, nor used by mbed Client
 conf unset MBEDTLS_NET_C
 conf unset MBEDTLS_TIMING_C