diff --git a/extras/wificfg/wificfg.c b/extras/wificfg/wificfg.c
index 60c9b3d..ef9f701 100644
--- a/extras/wificfg/wificfg.c
+++ b/extras/wificfg/wificfg.c
@@ -54,9 +54,9 @@
 #endif
 
 
-char *wificfg_default_ssid = "EOR_%02X%02X%02X";
-char *wificfg_default_password = "esp-open-rtos";
-char *wificfg_default_hostname = "eor-%02x%02x%02x";
+const char *wificfg_default_ssid = "EOR_%02X%02X%02X";
+const char *wificfg_default_password = "esp-open-rtos";
+const char *wificfg_default_hostname = "eor-%02x%02x%02x";
 
 /* The http task stack allocates a single buffer to do much of it's work. */
 #define HTTP_BUFFER_SIZE 54
@@ -644,7 +644,7 @@ static int handle_wificfg_index(int s, wificfg_method method,
         if (wificfg_write_string_chunk(s, "<dt>Newlib version</dt><dd>" _NEWLIB_VERSION "</dd>", buf, len) < 0) return -1;
 
         enum sdk_sleep_type sleep_type = sdk_wifi_get_sleep_type();
-        char *sleep_type_str = "??";
+        const char *sleep_type_str = "??";
         switch (sleep_type) {
         case WIFI_SLEEP_NONE:
             sleep_type_str = "None";
diff --git a/extras/wificfg/wificfg.h b/extras/wificfg/wificfg.h
index 705b2f6..923d4b4 100644
--- a/extras/wificfg/wificfg.h
+++ b/extras/wificfg/wificfg.h
@@ -31,20 +31,20 @@ extern "C" {
  * three bytes of the mac address. This may be NULL to not default the ssid,
  * but the AP network will not run without a ssid.
  */
-extern char *wificfg_default_ssid;
+extern const char *wificfg_default_ssid;
 
 /*
  * A default password for the AP interface. This may be NULL to not default the
  * password, but the AP network will not run without a password. The minimum
  * length is 8 characters.
  */
-extern char *wificfg_default_password;
+extern const char *wificfg_default_password;
 
 /*
  * A default hostname printf format string. This may be NULL to not default the
  * hostname.
  */
-extern char *wificfg_default_hostname;
+extern const char *wificfg_default_hostname;
 
 /*
  * The web server parses the http method string in these enums. The ANY method