diff --git a/assets.h b/assets.h
index 33d52ed..b0bac13 100644
--- a/assets.h
+++ b/assets.h
@@ -104,8 +104,6 @@ static const char *LCR_internalDataFile =
   ":-k5k1 :f5120"
   " map end "
 
-  "#Rrep1;testmap;482f70f9 00000188:00c1:0089:0111:00b9:0091:0109:0028:0050:00c1:0093:0030:00d1:0069:0041:0020:0071:0013:0012:0023:0022:0050:0032:0020:0022:0060:0024:00bc:0044"
-
   // MAP 1:
   "#MLC1;4321 0 "
   ":*B2mL:!x6G:+L2H:+D38"                    // start, finish, CPs
@@ -359,6 +357,8 @@ static const char *LCR_internalDataFile =
   // fans:
   ":Vm1xI:Vm1z"
   ":-w0q1:-y0q1"
+
+  "#" // for user data file
 ;
 
 #define LCR_IMAGE_SIZE 64 ///< one-dimension resolution of bitmap image
diff --git a/data b/data
index 7a035ce..d9f40e5 100644
--- a/data
+++ b/data
@@ -1,4 +1,4 @@
-#Mmap2;4321 1 :=s0s0 :-u0s0 :;w0s0 :,y0s0 :.s0u0 :Is0w0 :'s1y0
+Mmap2;4321 1 :=s0s0 :-u0s0 :;w0s0 :,y0s0 :.s0u0 :Is0w0 :'s1y0
 #Bnomap
 #Rrep2;testmap;482f70f9 00000843:0173:0081:0029:0111:0039:0071:00a3:0061:0169:0051:00b3:0041:0073:0081:0033:0041:0033:0231:0030:0098:0029:0011:0163:00f1:0053:0081:0033:0051:0023:0031:00f0:0032:0023:0131:00b9:0081:0023:00a1:0119:00e1:00c9:0071:0039:00a1:00d3:0021:01f9:0091:0079:0091:0039:0051:0049:0021:0083:0031:0083:0031:0083:0061:0089:0121:00a0:0058:002c:0048:0061:0013:0150:0052:00c0:00a1:0053:0041:0043:0031:0020:0092:0063:0181:0010:00a2:0013:0071:00e0:0028:00e9:0078:00a9:0043:0032:0123:0042:0080:0038:004c:01a8:0050:0032:0033:0101
 #Btestmap;
@@ -31,3 +31,5 @@ ramps
 
 finish
 :!vdt :!vdA
+#RLCtiny1;00LCtiny1;8ecff5c0 000381:00a1:02b9:0041:0265:0061:029:0141:0263:0041:0043:0051:003:0041:0033:0031:0033:0052:00260042:0096:0092:0026:0022:0086:02e:001c:0072:0043:00f1:0033:012:0039:0061:0069:0041:00b5:0021:263:0031:00c9:0011
+#BLCtiny1;
diff --git a/game.h b/game.h
index d66717f..8e21301 100644
--- a/game.h
+++ b/game.h
@@ -243,8 +243,8 @@ static inline void LCR_gameDrawPixelXYSafe(unsigned int x, unsigned int y,
 
 #define LCR_MENU_STRING_SIZE 16
 
-#define LCR_RESOURCE_FILE_SEPARATOR '#'
-#define LCR_RESOURCE_FILE_SEPARATOR2 ';'
+#define LCR_DATA_FILE_SEPARATOR '#'
+#define LCR_DATA_FILE_SEPARATOR2 ';'
 
 #define LCR_FREE_CAMERA_STEP \
   ((LCR_SETTING_FREE_CAMERA_SPEED * LCR_GAME_UNIT / 8) \
@@ -611,7 +611,7 @@ void LCR_gameRewindDataFile(void)
 */
 char LCR_gameGetNextDataFileChar(void)
 {
-#if LCR_SETTING_ENABLE_RESOURCE_FILE
+#if LCR_SETTING_ENABLE_DATA_FILE
   char c;
 
   if (LCR_game.dataFile.state < 0) // external file?
@@ -653,7 +653,7 @@ char LCR_gameGetNextDataFileChar(void)
 char LCR_gameGetNextDataStrChar(void)
 {
   char c = LCR_gameGetNextDataFileChar();
-  return c != LCR_RESOURCE_FILE_SEPARATOR ? c : 0;
+  return c != LCR_DATA_FILE_SEPARATOR ? c : 0;
 }
 
 unsigned int LCR_countData(char magicNumber)
@@ -669,7 +669,7 @@ unsigned int LCR_countData(char magicNumber)
     if (c == magicNumber)
       result++;
 
-    while (c != 0 && c != LCR_RESOURCE_FILE_SEPARATOR)
+    while (c != 0 && c != LCR_DATA_FILE_SEPARATOR)
       c = LCR_gameGetNextDataFileChar();
 
     if (c == 0)
@@ -703,7 +703,7 @@ void LCR_seekDataByIndex(unsigned int index, char magicNumber)
         return;
     }
     
-    while (c != 0 && c != LCR_RESOURCE_FILE_SEPARATOR)
+    while (c != 0 && c != LCR_DATA_FILE_SEPARATOR)
       c = LCR_gameGetNextDataFileChar();
 
   } while (c);
@@ -727,8 +727,8 @@ uint8_t LCR_mapIsBeaten(const char *name)
 
         if (name[i] == 0)
         {
-          if (c < ' ' || c == LCR_RESOURCE_FILE_SEPARATOR ||
-            c == LCR_RESOURCE_FILE_SEPARATOR2 || c == 0)
+          if (c < ' ' || c == LCR_DATA_FILE_SEPARATOR ||
+            c == LCR_DATA_FILE_SEPARATOR2 || c == 0)
             return 1;
           else
             break;
@@ -749,26 +749,25 @@ uint8_t LCR_mapIsBeaten(const char *name)
 
 void LCR_gameLoadMap(unsigned int mapIndex)
 {
-  char mapName[LCR_MAP_NAME_MAX_LEN];
+  char name[LCR_MAP_NAME_MAX_LEN + 1];
+  name[0] = 0;
 
   LCR_seekDataByIndex(mapIndex,'M');
 
-  mapName[0] = 0;
-
   for (int i = 0; i < LCR_MAP_NAME_MAX_LEN; ++i)
   {
     char c = LCR_gameGetNextDataFileChar();
 
-    if (c == LCR_RESOURCE_FILE_SEPARATOR2 ||
-      c == LCR_RESOURCE_FILE_SEPARATOR || c == 0)
+    if (c == LCR_DATA_FILE_SEPARATOR2 ||
+      c == LCR_DATA_FILE_SEPARATOR || c == 0)
       break;
 
-    mapName[i] = c;
-    mapName[i + 1] = 0;
+    name[i] = c;
+    name[i + 1] = 0;
   }
 
-  LCR_mapLoadFromStr(LCR_gameGetNextDataStrChar,mapName);
-  LCR_game.mapBeaten = LCR_mapIsBeaten(mapName);
+  LCR_mapLoadFromStr(LCR_gameGetNextDataStrChar,name);
+  LCR_game.mapBeaten = LCR_mapIsBeaten(LCR_currentMap.name);
 }
 
 /**
@@ -791,8 +790,8 @@ unsigned int LCR_gameLoadReplay(unsigned int replayIndex)
   {
     c = LCR_gameGetNextDataFileChar();
   }
-  while (c && c != LCR_RESOURCE_FILE_SEPARATOR2 &&
-    c != LCR_RESOURCE_FILE_SEPARATOR);
+  while (c && c != LCR_DATA_FILE_SEPARATOR2 &&
+    c != LCR_DATA_FILE_SEPARATOR);
 
   if (!LCR_replayLoadFromStr(LCR_gameGetNextDataStrChar,
     &mapHash,&nameHash))
@@ -835,7 +834,7 @@ unsigned int LCR_gameLoadReplay(unsigned int replayIndex)
         mapIndex++;
       }
 
-      while (c != LCR_RESOURCE_FILE_SEPARATOR)
+      while (c != LCR_DATA_FILE_SEPARATOR)
       {
         if (c == 0)
           return -1;
@@ -869,6 +868,42 @@ void LCR_gameLoadMainMenuItems(void)
   LCR_game.menu.itemCount = 4;
 }
 
+#define LCR_GAME_DATA_FILE_BUFFER_SIZE 32
+
+char _LCR_gameDataFileBuffer[LCR_GAME_DATA_FILE_BUFFER_SIZE];
+
+/**
+  Appends a single character to the data file WITH buffering, i.e. actual write
+  is only performed when the buffer is filled OR when the character is a
+  newline (which can be used to force a flush).
+*/
+void _LCR_gameDataCharWrite(char c)
+{
+  uint8_t i = 0;
+
+  while (_LCR_gameDataFileBuffer[i])
+  {
+    if (i >= LCR_GAME_DATA_FILE_BUFFER_SIZE - 2)
+    {
+      _LCR_gameDataFileBuffer[i] = c;
+      LCR_appendDataStr(_LCR_gameDataFileBuffer);
+      _LCR_gameDataFileBuffer[0] = 0;
+      return;
+    }
+
+    i++;
+  }
+
+  _LCR_gameDataFileBuffer[i] = c;
+  _LCR_gameDataFileBuffer[i + 1] = 0;
+
+  if (c == 0 || c == '\n')
+  {
+    LCR_appendDataStr(_LCR_gameDataFileBuffer);
+    _LCR_gameDataFileBuffer[0] = 0;
+  }
+}
+
 /**
   Loads up to LCR_RESOURCE_ITEM_CHUNK items of given type, starting at given
   index (among items of the same type). This will also load the menu item names.
@@ -916,8 +951,8 @@ void LCR_gameLoadDataFileChunk(unsigned int startIndex, char magicNumber)
       }
       else if (i == 1 && state != 255)
       {
-        if (c == LCR_RESOURCE_FILE_SEPARATOR ||
-          c == LCR_RESOURCE_FILE_SEPARATOR2 ||
+        if (c == LCR_DATA_FILE_SEPARATOR ||
+          c == LCR_DATA_FILE_SEPARATOR2 ||
           state >= 1 + LCR_MENU_STRING_SIZE - 1)
         {
           state = 255;
@@ -932,7 +967,7 @@ void LCR_gameLoadDataFileChunk(unsigned int startIndex, char magicNumber)
         state++;
       }
 
-      if (c == LCR_RESOURCE_FILE_SEPARATOR)
+      if (c == LCR_DATA_FILE_SEPARATOR)
         state = 0;
     }
   }
@@ -1037,8 +1072,8 @@ void LCR_checkBeatenMaps(void)
       {
         c = LCR_gameGetNextDataFileChar();
 
-        if (c < ' ' || c == LCR_RESOURCE_FILE_SEPARATOR ||
-          c == LCR_RESOURCE_FILE_SEPARATOR2)
+        if (c < ' ' || c == LCR_DATA_FILE_SEPARATOR ||
+          c == LCR_DATA_FILE_SEPARATOR2)
           break;
 
         name[i] = c;
@@ -1063,7 +1098,7 @@ void LCR_checkBeatenMaps(void)
         }
     }
     else
-      while (c != 0 && c != LCR_RESOURCE_FILE_SEPARATOR)
+      while (c != 0 && c != LCR_DATA_FILE_SEPARATOR)
         c = LCR_gameGetNextDataFileChar();
 
     if (c == 0)
@@ -1202,14 +1237,20 @@ void LCR_gameDraw3DView(void)
   }
 }
 
-void _LCR_gameDataCharWrite(char c)
-{ // TODO
-  printf("%c",c);
-}
-
 void LCR_gameSaveReplay(void)
 {
   LCR_LOG0("saving replay");
+  _LCR_gameDataCharWrite(LCR_DATA_FILE_SEPARATOR);
+  _LCR_gameDataCharWrite('R');
+
+  for (int i = 0; i < LCR_MAP_NAME_MAX_LEN; ++i)
+    if (LCR_currentMap.name[i])
+  _LCR_gameDataCharWrite(LCR_currentMap.name[i]);
+    else
+      break;
+          
+  _LCR_gameDataCharWrite(';');
+
   LCR_replayOutputStr(_LCR_gameDataCharWrite);
   LCR_gamePopupMessage(LCR_texts[LCR_TEXTS_SAVED]);
 }
@@ -1525,7 +1566,20 @@ uint8_t LCR_gameStep(uint32_t time)
           !LCR_racing.playingReplay)
         {
           LCR_LOG1("map beaten");
-          // TODO
+          LCR_game.mapBeaten = 1;
+
+          // record that the map is beaten in the data file:
+          _LCR_gameDataCharWrite(LCR_DATA_FILE_SEPARATOR);
+          _LCR_gameDataCharWrite('B');
+
+          for (int i = 0; i < LCR_MAP_NAME_MAX_LEN; ++i)
+            if (LCR_currentMap.name[i])
+              _LCR_gameDataCharWrite(LCR_currentMap.name[i]);
+            else
+              break;
+
+          _LCR_gameDataCharWrite(';');
+          _LCR_gameDataCharWrite('\n');
         }
       }