diff --git a/stmhal/lcd.c b/stmhal/lcd.c
index cde6c36f67..ae453f0fc6 100644
--- a/stmhal/lcd.c
+++ b/stmhal/lcd.c
@@ -373,7 +373,7 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_lcd_light_obj, pyb_lcd_light);
 /// Write the string `str` to the screen.  It will appear immediately.
 STATIC mp_obj_t pyb_lcd_write(mp_obj_t self_in, mp_obj_t str) {
     pyb_lcd_obj_t *self = self_in;
-    mp_uint_t len;
+    size_t len;
     const char *data = mp_obj_str_get_data(str, &len);
     lcd_write_strn(self, data, len);
     return mp_const_none;
@@ -445,7 +445,7 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_lcd_pixel_obj, 4, 4, pyb_lcd_pixe
 STATIC mp_obj_t pyb_lcd_text(mp_uint_t n_args, const mp_obj_t *args) {
     // extract arguments
     pyb_lcd_obj_t *self = args[0];
-    mp_uint_t len;
+    size_t len;
     const char *data = mp_obj_str_get_data(args[1], &len);
     int x0 = mp_obj_get_int(args[2]);
     int y0 = mp_obj_get_int(args[3]);
diff --git a/stmhal/modnwcc3k.c b/stmhal/modnwcc3k.c
index e1426c0556..ae403cacd6 100644
--- a/stmhal/modnwcc3k.c
+++ b/stmhal/modnwcc3k.c
@@ -477,11 +477,11 @@ STATIC mp_obj_t cc3k_connect(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_
     mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
 
     // get ssid
-    mp_uint_t ssid_len;
+    size_t ssid_len;
     const char *ssid = mp_obj_str_get_data(args[0].u_obj, &ssid_len);
 
     // get key and sec
-    mp_uint_t key_len = 0;
+    size_t key_len = 0;
     const char *key = NULL;
     mp_uint_t sec = WLAN_SEC_UNSEC;
     if (args[1].u_obj != mp_const_none) {
diff --git a/stmhal/modusocket.c b/stmhal/modusocket.c
index 7ff8902640..d066501d02 100644
--- a/stmhal/modusocket.c
+++ b/stmhal/modusocket.c
@@ -388,7 +388,7 @@ STATIC const mp_obj_type_t socket_type = {
 
 // function usocket.getaddrinfo(host, port)
 STATIC mp_obj_t mod_usocket_getaddrinfo(mp_obj_t host_in, mp_obj_t port_in) {
-    mp_uint_t hlen;
+    size_t hlen;
     const char *host = mp_obj_str_get_data(host_in, &hlen);
     mp_int_t port = mp_obj_get_int(port_in);