diff --git a/Cart_Reader/SMS.ino b/Cart_Reader/SMS.ino
index e4b9480..0cea120 100644
--- a/Cart_Reader/SMS.ino
+++ b/Cart_Reader/SMS.ino
@@ -68,6 +68,7 @@ void _smsMenu() {
       // Change working dir to root
       sd.chdir("/");
       readROM_SMS();
+      compare_checksum_sms();
 #ifdef global_log
       save_log();
 #endif
@@ -592,6 +593,88 @@ void readROM_SMS() {
   myFile.close();
 }
 
+inline uint32_t updateCRC_SMS(uint8_t ch, uint32_t crc) {
+  uint32_t idx = ((crc) ^ (ch)) & 0xff;
+  uint32_t tab_value = pgm_read_dword(crc_32_tab + idx);
+  return tab_value ^ ((crc) >> 8);
+}
+
+// Calculate rom's CRC32 from SD
+uint32_t crcSMS(char* fileName, char* folder) {
+  if (myFile.open(fileName, O_READ)) {
+    uint32_t oldcrc32 = 0xFFFFFFFF;
+
+    for (unsigned long currByte = 0; currByte < (myFile.fileSize() / 512); currByte++) {
+      myFile.read(sdBuffer, 512);
+      for (int c = 0; c < 512; c++) {
+        oldcrc32 = updateCRC_SMS(sdBuffer[c], oldcrc32);
+      }
+    }
+    // Close the file:
+    myFile.close();
+    return ~oldcrc32;
+  }
+  else {
+    print_Error(F("File not found"), true);
+  }
+}
+
+
+void compare_checksum_sms() {
+#ifdef no-intro
+  //CRC32
+  char crcStr[9];
+  sprintf(crcStr, "%08lX", crcSMS(fileName, folder));
+  // Print checksum
+  print_Msg("CRC32: ");
+  print_Msg(crcStr);
+
+  //Search for CRC32 in file
+  char gamename[100];
+  char crc_search[9];
+
+  //go to root
+  sd.chdir();
+  if (myFile.open("sms.txt", O_READ)) {
+    //Search for same CRC in list
+    while (myFile.available()) {
+      //Read 2 lines (game name and CRC)
+      get_line(gamename, &myFile, 96);
+      get_line(crc_search, &myFile, 9);
+      skip_line(&myFile); //Skip every 3rd line
+
+      //if checksum search successful, rename the file and end search
+      if (strcmp(crc_search, crcStr) == 0)
+      {
+        // Close the file:
+        myFile.close();
+
+        print_Msg(" -> ");
+        println_Msg(gamename);
+
+        // Rename file to no-intro
+        sd.chdir(folder);
+        if (myFile.open(fileName, O_READ)) {
+          myFile.rename(gamename);
+          // Close the file:
+          myFile.close();
+        }
+        break;
+      }
+    }
+    if (strcmp(crc_search, crcStr) != 0)
+    {
+      println_Msg(" -> Not found");
+    }
+  }
+  else {
+    println_Msg(" -> sms.txt not found");
+  }
+#else
+  println_Msg("");
+#endif
+}
+
 // Read SRAM and save to the SD card
 void readSRAM_SMS() {
   // Get name, add extension and convert to char array for sd lib
diff --git a/Cart_Reader/options.h b/Cart_Reader/options.h
index 5861195..769b0a8 100644
--- a/Cart_Reader/options.h
+++ b/Cart_Reader/options.h
@@ -69,7 +69,7 @@
 // #define clockgen_installed
 
 //******************************************
-// GB OPTIONS
+// GB, SMS database options
 //******************************************
 // Renames ROM if found in database (slow)
 // #define no-intro