diff --git a/src/mraa.c b/src/mraa.c
index c3050f4..707f1c5 100644
--- a/src/mraa.c
+++ b/src/mraa.c
@@ -1027,8 +1027,12 @@ mraa_add_subplatform(mraa_platform_t subplatformtype, const char* uart_dev)
 #if defined(FIRMATA)
     if (subplatformtype == MRAA_GENERIC_FIRMATA) {
         if (plat->sub_platform != NULL) {
-            syslog(LOG_NOTICE, "mraa: Failed to add firmata subplatform");
-            return MRAA_ERROR_INVALID_PARAMETER;
+            if (plat->sub_platform->platform_type == subplatformtype) {
+                syslog(LOG_NOTICE, "mraa: Firmata subplatform already present");
+                return MRAA_SUCCESS;
+            }
+            syslog(LOG_NOTICE, "mraa: We don't support multiple firmata subplatforms!");
+            return MRAA_ERROR_FEATURE_NOT_SUPPORTED;
         }
         if (mraa_firmata_platform(plat, uart_dev) == MRAA_GENERIC_FIRMATA) {
             syslog(LOG_NOTICE, "mraa: Added firmata subplatform");