diff --git a/drivers/cc3000/src/inet_ntop.c b/drivers/cc3000/src/inet_ntop.c
index c03ac44cd8..83242efa00 100644
--- a/drivers/cc3000/src/inet_ntop.c
+++ b/drivers/cc3000/src/inet_ntop.c
@@ -15,12 +15,16 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#include <std.h>
 #include <string.h>
 #include "cc3000_common.h"
 #include "socket.h"
 #include "inet_ntop.h"
 
+// We can't include stdio.h because it defines _types_fd_set, but we
+// need to use the CC3000 version of this type.  So we must provide
+// our own declaration of snprintf.  Grrr.
+int snprintf(char *str, size_t size, const char *fmt, ...);
+
 #define IN6ADDRSZ       16
 #define INADDRSZ         4
 #define INT16SZ          2
diff --git a/stmhal/modnwcc3k.c b/stmhal/modnwcc3k.c
index fc412a7bb5..5236c3bdc1 100644
--- a/stmhal/modnwcc3k.c
+++ b/stmhal/modnwcc3k.c
@@ -24,10 +24,6 @@
  * THE SOFTWARE.
  */
 
-// We can't include stdio.h because it defines _types_fd_set, but we
-// need to use the CC3000 version of this type.
-
-#include <std.h>
 #include <string.h>
 #include <stdarg.h>
 #include <errno.h>
@@ -531,9 +527,9 @@ STATIC mp_obj_t cc3k_ifconfig(mp_obj_t self_in) {
     mod_network_convert_ipv4_endianness(ipconfig.aucDHCPServer);
 
     // render MAC address
-    char mac_str[18];
+    VSTR_FIXED(mac_vstr, 18);
     const uint8_t *mac = ipconfig.uaMacAddr;
-    mp_uint_t mac_len = snprintf(mac_str, 18, "%02X:%02x:%02x:%02x:%02x:%02x", mac[5], mac[4], mac[3], mac[2], mac[1], mac[0]);
+    vstr_printf(&mac_vstr, "%02x:%02x:%02x:%02x:%02x:%02x", mac[5], mac[4], mac[3], mac[2], mac[1], mac[0]);
 
     // create and return tuple with ifconfig info
     mp_obj_t tuple[7] = {
@@ -542,7 +538,7 @@ STATIC mp_obj_t cc3k_ifconfig(mp_obj_t self_in) {
         mod_network_format_ipv4_addr(ipconfig.aucDefaultGateway),
         mod_network_format_ipv4_addr(ipconfig.aucDNSServer),
         mod_network_format_ipv4_addr(ipconfig.aucDHCPServer),
-        mp_obj_new_str(mac_str, mac_len, false),
+        mp_obj_new_str(mac_vstr.buf, mac_vstr.len, false),
         mp_obj_new_str((const char*)ipconfig.uaSSID, strlen((const char*)ipconfig.uaSSID), false),
     };
     return mp_obj_new_tuple(MP_ARRAY_SIZE(tuple), tuple);
@@ -566,7 +562,7 @@ STATIC mp_obj_t cc3k_patch_program(mp_obj_t self_in, mp_obj_t key_in) {
     if (key[0] == 'p' && key[1] == 'g' && key[2] == 'm' && key[3] == '\0') {
         patch_prog_start();
     } else {
-        printf("pass 'pgm' as argument in order to program\n");
+        mp_print_str(&mp_plat_print, "pass 'pgm' as argument in order to program\n");
     }
     return mp_const_none;
 }
diff --git a/stmhal/std.h b/stmhal/std.h
deleted file mode 100644
index eb14a4f9a8..0000000000
--- a/stmhal/std.h
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * This file is part of the Micro Python project, http://micropython.org/
- *
- * The MIT License (MIT)
- *
- * Copyright (c) 2013, 2014 Damien P. George
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-typedef unsigned int size_t;
-
-void *memcpy(void *dest, const void *src, size_t n);
-void *memmove(void *dest, const void *src, size_t n);
-void *memset(void *s, int c, size_t n);
-
-size_t strlen(const char *str);
-int strcmp(const char *s1, const char *s2);
-int strncmp(const char *s1, const char *s2, size_t n);
-char *strcpy(char *dest, const char *src);
-char *strcat(char *dest, const char *src);
-char *strchr(const char *s, int c);
-char *strstr(const char *haystack, const char *needle);
-
-int printf(const char *fmt, ...);
-int snprintf(char *str, size_t size, const char *fmt, ...);