diff --git a/.travis.yml b/.travis.yml
index b6b0ea70e7..8e3d18fdfe 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,6 +17,7 @@ script:
   - make -C bare-arm
   - make -C qemu-arm
   - make -C stmhal
+  - make -C stmhal -B MICROPY_PY_WIZNET5K=1 MICROPY_PY_CC3K=1
   - make -C stmhal BOARD=STM32F4DISC
   - make -C teensy
   - make -C windows CROSS_COMPILE=i586-mingw32msvc-
diff --git a/stmhal/modcc3k.c b/stmhal/modcc3k.c
index ab7ff1928f..7c35e76f68 100644
--- a/stmhal/modcc3k.c
+++ b/stmhal/modcc3k.c
@@ -381,7 +381,7 @@ STATIC mp_obj_t cc3k_socket_send(mp_obj_t self_in, mp_obj_t buf_in) {
     mp_int_t bytes = 0;
     while (bytes < bufinfo.len) {
         int n = MIN((bufinfo.len - bytes), MAX_TX_PACKET);
-        n = CC3000_EXPORT(send)(self->fd, bufinfo.buf + bytes, n, 0);
+        n = CC3000_EXPORT(send)(self->fd, (uint8_t*)bufinfo.buf + bytes, n, 0);
         if (n <= 0) {
             nlr_raise(mp_obj_new_exception_arg1(&mp_type_OSError, MP_OBJ_NEW_SMALL_INT(CC3000_EXPORT(errno))));
         }