diff --git a/examples/ESP8266_RTOS/user/Makefile b/examples/ESP8266_RTOS/user/Makefile
index 532f357ac7dcaecc5d2b003caba2e73456f0013f..cbfdd4d07b7834469fbaf17e3a41254ce16c3a91 100644
--- a/examples/ESP8266_RTOS/user/Makefile
+++ b/examples/ESP8266_RTOS/user/Makefile
@@ -25,7 +25,6 @@ endif
 #
 DEFINES += -DCS_PLATFORM=3 \
            -DMG_NO_BSD_SOCKETS=1 \
-           -DMG_DISABLE_FILESYSTEM=1 \
            -DRTOS_SDK -DMG_LWIP -DLWIP_TIMEVAL_PRIVATE=0 \
            -DMG_INTERNAL=
 
diff --git a/mongoose.c b/mongoose.c
index 08ed1d2d1933b4d495edb52744ca9f661c37ecc8..69f4faf16c8a686498a5c26f7cb7cc95fcd63c25 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -45,9 +45,7 @@
 
 #ifdef PICOTCP
 #define NO_LIBC
-#define MG_DISABLE_FILESYSTEM
 #define MG_DISABLE_POPEN
-#define MG_DISABLE_DIRECTORY_LISTING
 #define MG_DISABLE_SOCKETPAIR
 #define MG_DISABLE_PFS
 #endif
@@ -73,11 +71,13 @@ MG_INTERNAL void mg_remove_conn(struct mg_connection *c);
 MG_INTERNAL struct mg_connection *mg_create_connection(
     struct mg_mgr *mgr, mg_event_handler_t callback,
     struct mg_add_sock_opts opts);
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
 MG_INTERNAL int mg_uri_to_local_path(struct http_message *hm,
                                      const struct mg_serve_http_opts *opts,
                                      char **local_path,
                                      struct mg_str *remainder);
+MG_INTERNAL time_t mg_parse_date_string(const char *datetime);
+MG_INTERNAL int mg_is_not_modified(struct http_message *hm, cs_stat_t *st);
 #endif
 #ifdef _WIN32
 /* Retur value is the same as for MultiByteToWideChar. */
@@ -99,11 +99,6 @@ MG_INTERNAL size_t mg_handle_chunked(struct mg_connection *nc,
                                      struct http_message *hm, char *buf,
                                      size_t blen);
 
-#if !MG_DISABLE_FILESYSTEM
-MG_INTERNAL time_t mg_parse_date_string(const char *datetime);
-MG_INTERNAL int mg_is_not_modified(struct http_message *hm, cs_stat_t *st);
-#endif
-
 struct ctl_msg {
   mg_event_handler_t callback;
   char message[MG_CTL_MSG_MESSAGE_SIZE];
@@ -3880,7 +3875,7 @@ struct mg_http_multipart_stream {
 };
 
 struct mg_http_proto_data {
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
   struct mg_http_proto_data_file file;
 #endif
 #if MG_ENABLE_CGI
@@ -3916,7 +3911,7 @@ static void mg_http_free_proto_data_mp_stream(
 }
 #endif
 
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
 static void mg_http_free_proto_data_file(struct mg_http_proto_data_file *d) {
   if (d != NULL) {
     if (d->fp != NULL) {
@@ -3942,7 +3937,7 @@ static void mg_http_free_proto_data_endpoints(struct mg_http_endpoint **ep) {
 
 static void mg_http_conn_destructor(void *proto_data) {
   struct mg_http_proto_data *pd = (struct mg_http_proto_data *) proto_data;
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
   mg_http_free_proto_data_file(&pd->file);
 #endif
 #if MG_ENABLE_CGI
@@ -3955,7 +3950,7 @@ static void mg_http_conn_destructor(void *proto_data) {
   free(proto_data);
 }
 
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
 
 #define MIME_ENTRY(_ext, _type) \
   { _ext, sizeof(_ext) - 1, _type }
@@ -4482,7 +4477,7 @@ static void mg_ws_handshake(struct mg_connection *nc,
 
 #endif /* MG_DISABLE_HTTP_WEBSOCKET */
 
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
 static void mg_http_transfer_file_data(struct mg_connection *nc) {
   struct mg_http_proto_data *pd = mg_http_get_proto_data(nc);
   char buf[MG_MAX_HTTP_SEND_MBUF];
@@ -4532,7 +4527,7 @@ static void mg_http_transfer_file_data(struct mg_connection *nc) {
   }
 #endif
 }
-#endif /* MG_DISABLE_FILESYSTEM */
+#endif /* MG_ENABLE_FILESYSTEM */
 
 /*
  * Parse chunked-encoded buffer. Return 0 if the buffer is not encoded, or
@@ -4736,7 +4731,7 @@ void mg_http_handler(struct mg_connection *nc, int ev, void *ev_data) {
     }
   }
 
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
   if (pd->file.fp != NULL) {
     mg_http_transfer_file_data(nc);
   }
@@ -5380,12 +5375,7 @@ void mg_send_head(struct mg_connection *c, int status_code,
   mg_send(c, "\r\n", 2);
 }
 
-#if MG_DISABLE_FILESYSTEM
-void mg_serve_http(struct mg_connection *nc, struct http_message *hm,
-                   struct mg_serve_http_opts opts) {
-  mg_send_head(nc, 501, 0, NULL);
-}
-#else
+#if MG_ENABLE_FILESYSTEM
 static void mg_http_send_error(struct mg_connection *nc, int code,
                                const char *reason) {
   if (!reason) reason = "";
@@ -5883,7 +5873,7 @@ int mg_http_parse_header(struct mg_str *hdr, const char *var_name, char *buf,
   return len;
 }
 
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
 static int mg_is_file_hidden(const char *path,
                              const struct mg_serve_http_opts *opts,
                              int exclude_specials) {
@@ -6045,7 +6035,7 @@ static int mg_is_authorized(struct http_message *hm, const char *path,
 }
 #endif
 
-#if !MG_DISABLE_DIRECTORY_LISTING
+#if MG_ENABLE_DIRECTORY_LISTING
 static size_t mg_url_encode(const char *src, size_t s_len, char *dst,
                             size_t dst_len) {
   static const char *dont_escape = "._-$,;~()/";
@@ -6198,7 +6188,7 @@ static void mg_send_directory_listing(struct mg_connection *nc, const char *dir,
   /* TODO(rojer): Remove when cesanta/dev/issues/197 is fixed. */
   nc->flags |= MG_F_SEND_AND_CLOSE;
 }
-#endif /* MG_DISABLE_DIRECTORY_LISTING */
+#endif /* MG_ENABLE_DIRECTORY_LISTING */
 
 /*
  * Given a directory path, find one of the files specified in the
@@ -6578,7 +6568,7 @@ MG_INTERNAL void mg_send_http_file(struct mg_connection *nc, char *path,
   } else if (!mg_vcmp(&hm->method, "OPTIONS")) {
     mg_http_send_options(nc);
   } else if (is_directory && index_file == NULL) {
-#if !MG_DISABLE_DIRECTORY_LISTING
+#if MG_ENABLE_DIRECTORY_LISTING
     if (strcmp(opts->enable_directory_listing, "yes") == 0) {
       mg_send_directory_listing(nc, path, hm, opts);
     } else {
@@ -6654,7 +6644,7 @@ void mg_serve_http(struct mg_connection *nc, struct http_message *hm,
   }
 }
 
-#endif /* MG_DISABLE_FILESYSTEM */
+#endif /* MG_ENABLE_FILESYSTEM */
 
 /* returns 0 on success, -1 on error */
 static int mg_http_common_url_parse(const char *url, const char *schema,
@@ -7667,7 +7657,7 @@ int mg_casecmp(const char *s1, const char *s2) {
   return mg_ncasecmp(s1, s2, (size_t) ~0);
 }
 
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
 int mg_stat(const char *path, cs_stat_t *st) {
 #ifdef _WIN32
   wchar_t wpath[MAX_PATH_SIZE];
@@ -7830,7 +7820,7 @@ void mg_hexdump_connection(struct mg_connection *nc, const char *path,
     fp = stdout;
   } else if (strcmp(path, "--") == 0) {
     fp = stderr;
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
   } else {
     fp = fopen(path, "a");
 #endif
@@ -9019,7 +9009,7 @@ static int mg_get_ip_address_of_nameserver(char *name, size_t name_len) {
     }
     RegCloseKey(hKey);
   }
-#elif !MG_DISABLE_FILESYSTEM
+#elif MG_ENABLE_FILESYSTEM
   FILE *fp;
   char line[512];
 
@@ -9045,7 +9035,7 @@ static int mg_get_ip_address_of_nameserver(char *name, size_t name_len) {
 }
 
 int mg_resolve_from_hosts_file(const char *name, union socket_address *usa) {
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
   /* TODO(mkm) cache /etc/hosts */
   FILE *fp;
   char line[1024];
@@ -9075,6 +9065,9 @@ int mg_resolve_from_hosts_file(const char *name, union socket_address *usa) {
   }
 
   fclose(fp);
+#else
+  (void) name;
+  (void) usa;
 #endif
 
   return -1;
diff --git a/mongoose.h b/mongoose.h
index 4b9206124e88ebbc6475c3cb42e8b57cdcf6d9db..0c8e04d126eb7ecc446f32b597bf83079d19a063 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -245,6 +245,14 @@ typedef struct _stati64 cs_stat_t;
 #define CS_ENABLE_STDIO 1
 #endif
 
+#ifndef MG_ENABLE_DIRECTORY_LISTING
+#define MG_ENABLE_DIRECTORY_LISTING 1
+#endif
+
+#ifndef MG_ENABLE_FILESYSTEM
+#define MG_ENABLE_FILESYSTEM 1
+#endif
+
 #endif /* CS_PLATFORM == CS_P_WINDOWS */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_WINDOWS_H_ */
 #ifdef MG_MODULE_LINES
@@ -351,6 +359,14 @@ typedef struct stat cs_stat_t;
 #define CS_ENABLE_STDIO 1
 #endif
 
+#ifndef MG_ENABLE_DIRECTORY_LISTING
+#define MG_ENABLE_DIRECTORY_LISTING 1
+#endif
+
+#ifndef MG_ENABLE_FILESYSTEM
+#define MG_ENABLE_FILESYSTEM 1
+#endif
+
 #endif /* CS_PLATFORM == CS_P_UNIX */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_UNIX_H_ */
 #ifdef MG_MODULE_LINES
@@ -445,9 +461,6 @@ void mg_lwip_set_keepalive_params(struct mg_connection *nc, int idle,
 #define MG_DISABLE_SOCKETPAIR 1
 #define MG_DISABLE_SYNC_RESOLVER 1
 #define MG_DISABLE_POPEN 1
-#define MG_DISABLE_DAV 1
-#define MG_DISABLE_DIRECTORY_LISTING 1
-#define MG_DISABLE_FILESYSTEM 1
 
 /*
  * CC3100 SDK and STM32 SDK include headers w/out path, just like
@@ -504,10 +517,10 @@ int inet_pton(int af, const char *src, void *dst);
 #define MG_DISABLE_SOCKETPAIR 1
 #define MG_DISABLE_SYNC_RESOLVER 1
 #define MG_DISABLE_POPEN 1
+
 /* Only SPIFFS supports directories, SLFS does not. */
-#ifndef CC3200_FS_SPIFFS
-#define MG_DISABLE_DAV 1
-#define MG_DISABLE_DIRECTORY_LISTING 1
+#if defined(CC3200_FS_SPIFFS) && !defined(MG_ENABLE_DIRECTORY_LISTING)
+#define MG_ENABLE_DIRECTORY_LISTING 1
 #endif
 
 /* Amalgamated: #include "common/platforms/simplelink/cs_simplelink.h" */
@@ -598,6 +611,10 @@ struct dirent *readdir(DIR *dir);
 #define MG_FS_SLFS
 #endif
 
+#if (defined(CC3200_FS_SPIFFS) || defined(CC3200_FS_SLFS)) && !defined(MG_ENABLE_FILESYSTEM)
+#define MG_ENABLE_FILESYSTEM 1
+#endif
+
 #ifndef CS_ENABLE_STDIO
 #define CS_ENABLE_STDIO 1
 #endif
@@ -638,7 +655,6 @@ struct dirent *readdir(DIR *dir);
 #define MG_DISABLE_SYNC_RESOLVER 1
 #define MG_DISABLE_POPEN 1
 #define MG_DISABLE_DAV 1
-#define MG_DISABLE_DIRECTORY_LISTING 1
 
 /* Amalgamated: #include "common/platforms/simplelink/cs_simplelink.h" */
 
@@ -709,6 +725,10 @@ int _stat(const char *pathname, struct stat *st);
 #define CS_ENABLE_STDIO 1
 #endif
 
+#if (defined(CC3200_FS_SPIFFS) || defined(CC3200_FS_SLFS)) && !defined(MG_ENABLE_FILESYSTEM)
+#define MG_ENABLE_FILESYSTEM 1
+#endif
+
 #ifdef __cplusplus
 }
 #endif
@@ -1186,18 +1206,10 @@ const char *c_strnstr(const char *s, const char *find, size_t slen);
 #ifndef CS_MONGOOSE_SRC_FEATURES_H_
 #define CS_MONGOOSE_SRC_FEATURES_H_
 
-#ifndef MG_DISABLE_DIRECTORY_LISTING
-#define MG_DISABLE_DIRECTORY_LISTING 0
-#endif
-
 #ifndef MG_DISABLE_DNS
 #define MG_DISABLE_DNS 0
 #endif
 
-#ifndef MG_DISABLE_FILESYSTEM
-#define MG_DISABLE_FILESYSTEM 0
-#endif
-
 #ifndef MG_DISABLE_HTTP_DIGEST_AUTH
 #define MG_DISABLE_HTTP_DIGEST_AUTH 0
 #endif
@@ -1258,6 +1270,10 @@ const char *c_strnstr(const char *s, const char *find, size_t slen);
 #define MG_ENABLE_DEBUG 0
 #endif
 
+#ifndef MG_ENABLE_DIRECTORY_LISTING
+#define MG_ENABLE_DIRECTORY_LISTING 0
+#endif
+
 #ifndef MG_ENABLE_DNS_SERVER
 #define MG_ENABLE_DNS_SERVER 0
 #endif
@@ -1266,6 +1282,10 @@ const char *c_strnstr(const char *s, const char *find, size_t slen);
 #define MG_ENABLE_FAKE_DAVLOCK 0
 #endif
 
+#ifndef MG_ENABLE_FILESYSTEM
+#define MG_ENABLE_FILESYSTEM 0
+#endif
+
 #ifndef MG_ENABLE_GETADDRINFO
 #define MG_ENABLE_GETADDRINFO 0
 #endif
@@ -1318,12 +1338,6 @@ const char *c_strnstr(const char *s, const char *find, size_t slen);
 #define CS_ENABLE_DEBUG 1
 #endif
 
-/* All of the below features depend on filesystem access, disable them. */
-#if MG_DISABLE_FILESYSTEM
-#undef MG_DISABLE_DIRECTORY_LISTING
-#define MG_DISABLE_DIRECTORY_LISTING 1
-#endif /* MG_DISABLE_FILESYSTEM */
-
 #ifdef MG_NO_BSD_SOCKETS
 #undef MG_DISABLE_SYNC_RESOLVER
 #define MG_DISABLE_SYNC_RESOLVER 1
@@ -2108,7 +2122,7 @@ int mg_base64_decode(const unsigned char *s, int len, char *dst);
  */
 void mg_base64_encode(const unsigned char *src, int src_len, char *dst);
 
-#if !MG_DISABLE_FILESYSTEM
+#if MG_ENABLE_FILESYSTEM
 /*
  * Performs a 64-bit `stat()` call against a given file.
  *
@@ -2135,7 +2149,7 @@ FILE *mg_fopen(const char *path, const char *mode);
  * Return value is the same as for the `open()` syscall.
  */
 int mg_open(const char *path, int flag, int mode);
-#endif /* MG_DISABLE_FILESYSTEM */
+#endif /* MG_ENABLE_FILESYSTEM */
 
 #if MG_ENABLE_THREADS
 /*
@@ -2683,6 +2697,7 @@ size_t mg_parse_multipart(const char *buf, size_t buf_len, char *var_name,
 int mg_get_http_var(const struct mg_str *buf, const char *name, char *dst,
                     size_t dst_len);
 
+#if MG_ENABLE_FILESYSTEM
 /*
  * This structure defines how `mg_serve_http()` works.
  * Best practice is to set only required settings, and leave the rest as NULL.
@@ -2884,6 +2899,7 @@ void mg_serve_http(struct mg_connection *nc, struct http_message *hm,
 void mg_http_serve_file(struct mg_connection *nc, struct http_message *hm,
                         const char *path, const struct mg_str mime_type,
                         const struct mg_str extra_headers);
+#endif /* MG_ENABLE_FILESYSTEM */
 
 /*
  * Registers a callback for a specified http endpoint