diff --git a/Marlin/Configuration_adv.h b/Marlin/Configuration_adv.h
index b39e9e1722..eb54053199 100644
--- a/Marlin/Configuration_adv.h
+++ b/Marlin/Configuration_adv.h
@@ -1256,6 +1256,15 @@
   // This allows hosts to request long names for files and folders with M33
   //#define LONG_FILENAME_HOST_SUPPORT
 
+  //M20 Configuration
+  //#define M20_Reports_Directory_Names // Enable this to report each directory on the SD card in addition to any GCODE files
+  #if ENABLED(LONG_FILENAME_HOST_SUPPORT)
+    //LONG_FILENAME_HOST_SUPPORT allows M20 to return LONG or DOS8.3 filenames to the host. Default setting can be setup here. -> If both are disabled, M20 defaults to the DOS names
+    //If both are enabled, then M20 will report back this format for each item:     [DOS8.3 Name] --> [Long_FileName]  [Size in bytes]
+    #define M20_Reports_DOS_FileNames 
+    //#define M20_Reports_LONG_FileNames
+  #endif
+  
   // Enable this option to scroll long filenames in the SD card menu
   //#define SCROLL_LONG_FILENAMES
 
diff --git a/Marlin/src/gcode/sd/M20.cpp b/Marlin/src/gcode/sd/M20.cpp
index 7ac4affdae..fb218fed5f 100644
--- a/Marlin/src/gcode/sd/M20.cpp
+++ b/Marlin/src/gcode/sd/M20.cpp
@@ -32,9 +32,36 @@
  */
 void GcodeSuite::M20() {
   if (card.flag.mounted) {
-    SERIAL_ECHOLNPGM(STR_BEGIN_FILE_LIST);
-    card.ls();
-    SERIAL_ECHOLNPGM(STR_END_FILE_LIST);
+    if ( parser.seen('S' ) and parser.seen('L' ) ) {
+        card.ls(TRUE,TRUE);
+    
+    } else if ( parser.seen('S' ) ) {
+        card.ls(TRUE,FALSE); // Request Short (default DSoc 8,3) filenames if user used 'M20 S'
+    
+    } else if ( parser.seen('L' ) ) {
+        #if ENABLED(LONG_FILENAME_HOST_SUPPORT)
+          card.ls(FALSE,TRUE); // Request Short (default DSoc 8,3) filenames if user used 'M20 S'
+        #else
+          SERIAL_ECHOLNPGM("ERROR: Long_FileName_Host_Support Not Enabled!");
+        #endif
+    
+    } else {
+        #if ENABLED(LONG_FILENAME_HOST_SUPPORT) 
+    
+          #if ( ENABLED(M20_Reports_LONG_FileNames) and ENABLED(M20_Reports_DOS_FileNames) )
+            card.ls(TRUE,TRUE);
+
+          #elif ENABLED(M20_Reports_LONG_FileNames)  
+            card.ls(FALSE,TRUE);
+
+          #elif ENABLED(M20_Reports_DOS_FileNames) 
+            card.ls(TRUE,FALSE);
+          #endif
+
+        #else
+          card.ls(TRUE,FALSE);
+        #endif
+    } 
   }
   else
     SERIAL_ECHO_MSG(STR_NO_MEDIA);
diff --git a/Marlin/src/gcode/sd/M33.cpp b/Marlin/src/gcode/sd/M33.cpp
index b611c8bc08..deb0047ce7 100644
--- a/Marlin/src/gcode/sd/M33.cpp
+++ b/Marlin/src/gcode/sd/M33.cpp
@@ -41,7 +41,7 @@
  */
 void GcodeSuite::M33() {
 
-  card.printLongPath(parser.string_arg);
+  card.printLongPath(parser.string_arg, true);
 
 }
 
diff --git a/Marlin/src/sd/cardreader.cpp b/Marlin/src/sd/cardreader.cpp
index a633440ff6..5dae729097 100644
--- a/Marlin/src/sd/cardreader.cpp
+++ b/Marlin/src/sd/cardreader.cpp
@@ -57,6 +57,8 @@
 #include "../core/debug_out.h"
 #include "../libs/hex_print.h"
 
+#include <strings.h> //Required for strcasecmp command to compile without warnings in VS_Code
+
 // public:
 
 card_flags_t CardReader::flag;
@@ -154,6 +156,7 @@ CardReader::CardReader() {
 
 //
 // Get a DOS 8.3 filename in its useful form
+// Requires a file specified
 //
 char *createFilename(char * const buffer, const dir_t &p) {
   char *pos = buffer;
@@ -222,20 +225,113 @@ void CardReader::selectByIndex(SdFile dir, const uint8_t index) {
 //
 // Get file/folder info for an item by name
 //
-void CardReader::selectByName(SdFile dir, const char * const match) {
+void CardReader::selectByName(SdFile dir, const char * const match, boolean debug/*=false*/) {
   dir_t p;
   for (uint8_t cnt = 0; dir.readDir(&p, longFilename) > 0; cnt++) {
     if (is_dir_or_gcode(p)) {
       createFilename(filename, p);
-      if (strcasecmp(match, filename) == 0) return;
+      #if ENABLED(LONG_FILENAME_HOST_SUPPORT)
+        // Check for match using Long_File_Name or short filename
+        if ( (strcasecmp(match, longFilename) == 0) or (strcasecmp(match, filename) == 0) ) {
+          #if ENABLED(DEBUG_CARDREADER)
+            //debug = true;
+            if (debug) {
+              DEBUG_ECHOLN(" ");
+              DEBUG_ECHO(" DEBUG -SelectByName- LONG FileName: ");
+              DEBUG_ECHO(longFilename);
+              DEBUG_ECHO("-- Created FileName: ");
+              DEBUG_ECHO(filename);
+              DEBUG_ECHO(" -- Search Term: ");
+              DEBUG_ECHO(match);
+              DEBUG_ECHOLN(" -- Match Success: TRUE");
+            }
+          #endif
+
+          //This is a workaround if the filename IS the actual longfilename. This avoids reporting incorrect filenames such as "CURVE_~1.GCO" turning into "firmware.bin"
+          if ( ! (strncasecmp(filename, longFilename,3) == 0) ) {
+            #if ENABLED(DEBUG_CARDREADER)
+              //debug = true;
+              if ( debug) DEBUG_ECHOLNPAIR("DEBUG: MisMatch Found! Returning LongFileName as FileName");
+              if ( debug) DEBUG_ECHOLNPAIR("DEBUG: filename = ", filename);
+              if ( debug) DEBUG_ECHOLNPAIR("DEBUG: longFilename = ", longFilename);
+            #endif
+            strcpy(longFilename, filename);
+          }
+          return; 
+
+        } else {
+          //Match Not Found -> Wipe out the filenames to avoid returning a path to a different file
+          //if ( debug) DEBUG_ECHOLN("FALSE");
+          strcpy(filename, "");
+          strcpy(longFilename, "");
+        }
+      #else
+        if (strcasecmp(match, filename) == 0) {
+          if ( debug) DEBUG_ECHOLN(" DEBUG SelectByName - MatchFound");
+          return;
+        } else {
+          if ( debug) DEBUG_ECHOLN("FALSE");
+        }
+      #endif
     }
   }
 }
 
+#if ENABLED(M20_Reports_Directory_Names)
+  //
+  // Recursive method to list all directories within a folder
+  //
+  void CardReader::printDirListing(SdFile parent, boolean ReturnDOSFileNames, boolean ReturnLongFileNames, const char * const prepend/*=nullptr*/) {
+    dir_t p;
+    while (parent.readDir(&p, longFilename) > 0) {
+      if (DIR_IS_SUBDIR(&p)) {
+
+        // Get the short name for the item, which we know is a folder
+        char dosFilename[FILENAME_LENGTH];
+        createFilename(dosFilename, p);
+
+        // Allocate enough stack space to do the work ( full path to a folder, trailing slash, and nul )
+        const bool prepend_is_empty = (!prepend || prepend[0] == '\0');
+        const int lenPrePend = (prepend_is_empty ? 1 : strlen(prepend)) ;
+        const int len = lenPrePend + strlen(dosFilename) + 1 + 1;
+        char path[len];
+
+        // Append the FOLDERNAME12/ to the passed string.
+        // It contains the full path to the "parent" argument.
+        // We now have the full path to the item in this folder.
+        strcpy(path, prepend_is_empty ? "/" : prepend); // root slash if prepend is empty
+        strcat(path, dosFilename);                      // FILENAME_LENGTH characters maximum
+        strcat(path, "/");                              // 1 character
+
+        #if DISABLED(LONG_FILENAME_HOST_SUPPORT)
+          SERIAL_ECHOLN( path ); // All this work is already done!
+        #else
+          const int plen = lenPrePend + strlen(longFilename) + 2; 
+          // Generate the name of the file path then display
+          char Fpath[plen];
+          strcpy(Fpath, prepend_is_empty ? "/" : prepend); // root slash if prepend is empty       
+          strcat(Fpath, longFilename) ;
+          strcat(Fpath, "/");
+          SERIAL_ECHOLN( Fpath ); // Echo Result
+        #endif
+
+        // Get a new directory object using the full path
+        // and dive recursively into it.
+        SdFile child;
+        if (!child.open(&parent, dosFilename, O_READ)) {
+          SERIAL_ECHO_START();
+          SERIAL_ECHOLNPAIR(STR_SD_CANT_OPEN_SUBDIR, dosFilename);
+        }
+        printDirListing(child, ReturnDOSFileNames, ReturnLongFileNames, path);
+      }
+    }
+  }
+#endif
+
 //
 // Recursive method to list all files within a folder
 //
-void CardReader::printListing(SdFile parent, const char * const prepend/*=nullptr*/) {
+void CardReader::printListing(SdFile parent, boolean ReturnDOSFileNames, boolean ReturnLongFileNames, const char * const prepend/*=nullptr*/) {
   dir_t p;
   while (parent.readDir(&p, longFilename) > 0) {
     if (DIR_IS_SUBDIR(&p)) {
@@ -265,26 +361,49 @@ void CardReader::printListing(SdFile parent, const char * const prepend/*=nullpt
         SERIAL_ECHO_START();
         SERIAL_ECHOLNPAIR(STR_SD_CANT_OPEN_SUBDIR, dosFilename);
       }
-      printListing(child, path);
+      printListing(child, ReturnDOSFileNames, ReturnLongFileNames, path);
       // close() is done automatically by destructor of SdFile
     }
     else if (is_dir_or_gcode(p)) {
-      createFilename(filename, p);
-      if (prepend) SERIAL_ECHO(prepend);
-      SERIAL_ECHO(filename);
-      SERIAL_CHAR(' ');
-      SERIAL_ECHOLN(p.fileSize);
-    }
-  }
-}
+      createFilename(filename, p); //Parse the string and retrieve a DOS 8.3 FileName+
 
-//
-// List all files on the SD card
-//
-void CardReader::ls() {
-  if (flag.mounted) {
-    root.rewind();
-    printListing(root);
+      #if ENABLED(LONG_FILENAME_HOST_SUPPORT)
+
+        if (ReturnDOSFileNames) {//Print the DOS FileName & Path
+          if (prepend) { SERIAL_ECHO(prepend); }
+          SERIAL_ECHO(filename);
+        }
+
+        if (ReturnLongFileNames) {// Print the Long FileName
+          if (ReturnDOSFileNames) SERIAL_ECHO(" --> ");
+          if (prepend) {
+            //Allocate memory to concat everything before passing it into the PrintLongPath Routine
+            const int len = strlen(prepend) + strlen(filename) + 3;
+            char Fpath[len];
+            // Generate the name of the file path then display
+            strcpy(Fpath, prepend) ;
+            strcat(Fpath, filename) ;
+            printLongPath (Fpath, false);
+          }else {
+            //File exists on root
+            const int len = strlen(filename) + 3;
+            char Fpath[len];
+            strcpy(Fpath, "/") ;
+            strcat(Fpath, filename) ;
+            printLongPath(Fpath, false) ;
+          }
+        }
+      #else
+          //If Long_FileName_Host_Support is disabled -> Print the DOS8.3 filenames
+          if (prepend) { SERIAL_ECHO(prepend); }
+          SERIAL_ECHO(filename);
+      #endif
+
+      //Print the FileSize
+      SERIAL_CHAR(' ');
+      SERIAL_ECHO( p.fileSize  );
+      SERIAL_ECHOLN(" bytes");
+    }
   }
 }
 
@@ -293,7 +412,7 @@ void CardReader::ls() {
   //
   // Get a long pretty path based on a DOS 8.3 path
   //
-  void CardReader::printLongPath(char * const path) {
+  void CardReader::printLongPath(char * const path, boolean PrintLineReturn) {
 
     int i, pathLen = strlen(path);
 
@@ -344,11 +463,32 @@ void CardReader::ls() {
 
     } // while i<pathLen
 
-    SERIAL_EOL();
+    if (PrintLineReturn) SERIAL_EOL();
   }
 
 #endif // LONG_FILENAME_HOST_SUPPORT
 
+
+//
+// List all files on the SD card
+//
+void CardReader::ls(boolean ReturnDOSFileNames, boolean ReturnLongFileNames) {
+  if (flag.mounted) {
+    #if ENABLED(M20_Reports_Directory_Names)
+      SERIAL_ECHOLN("Begin Directory Listing") ;
+      root.rewind();
+      card.printDirListing(root, ReturnDOSFileNames,ReturnLongFileNames);
+      SERIAL_ECHOLN("End Directory Listing") ;
+      SERIAL_ECHOLN(" ") ;
+    #endif
+    SERIAL_ECHOLNPGM(STR_BEGIN_FILE_LIST);
+    root.rewind();
+    printListing(root, ReturnDOSFileNames, ReturnLongFileNames);
+    SERIAL_ECHOLNPGM(STR_END_FILE_LIST);
+  }
+}
+
+
 //
 // Echo the DOS 8.3 filename (and long filename, if any)
 //
@@ -573,7 +713,7 @@ void CardReader::openFileRead(char * const path, const uint8_t subcall_type/*=0*
   endFilePrint();
 
   SdFile *diveDir;
-  const char * const fname = diveToFile(true, diveDir, path);
+  const char * const fname = diveToFile(true, diveDir, path, false);
   if (!fname) return;
 
   if (file.open(diveDir, fname, O_READ)) {
@@ -608,7 +748,7 @@ void CardReader::openFileWrite(char * const path) {
   endFilePrint();
 
   SdFile *diveDir;
-  const char * const fname = diveToFile(false, diveDir, path);
+  const char * const fname = diveToFile(false, diveDir, path, true);
   if (!fname) return;
 
   #if ENABLED(SDCARD_READONLY)
@@ -633,7 +773,7 @@ void CardReader::openFileWrite(char * const path) {
 bool CardReader::fileExists(const char * const path) {
   if (!isMounted()) return false;
   SdFile *diveDir = nullptr;
-  const char * const fname = diveToFile(false, diveDir, path);
+  const char * const fname = diveToFile(false, diveDir, path, false);
   if (fname) {
     diveDir->rewind();
     selectByName(*diveDir, fname);
@@ -651,7 +791,7 @@ void CardReader::removeFile(const char * const name) {
   //endFilePrint();
 
   SdFile *curDir;
-  const char * const fname = diveToFile(false, curDir, name);
+  const char * const fname = diveToFile(false, curDir, name, false);
   if (!fname) return;
 
   #if ENABLED(SDCARD_READONLY)
@@ -684,7 +824,7 @@ void CardReader::write_command(char * const buf) {
   char* end = buf + strlen(buf) - 1;
 
   file.writeError = false;
-  if ((npos = strchr(buf, 'N'))) {
+  if ((npos = strchr(buf, 'N')) != nullptr) {
     begin = strchr(npos, ' ') + 1;
     end = strchr(npos, '*') - 1;
   }
@@ -795,7 +935,7 @@ uint16_t CardReader::countFilesInWorkDir() {
  *
  * A nullptr result indicates an unrecoverable error.
  */
-const char* CardReader::diveToFile(const bool update_cwd, SdFile*& diveDir, const char * const path, const bool echo/*=false*/) {
+const char* CardReader::diveToFile(const bool update_cwd, SdFile*& diveDir, const char * const path, const bool NewFile/*=false*/) {
   // Track both parent and subfolder
   static SdFile newDir1, newDir2;
   SdFile *sub = &newDir1, *startDir;
@@ -806,12 +946,15 @@ const char* CardReader::diveToFile(const bool update_cwd, SdFile*& diveDir, cons
   DEBUG_ECHOLNPAIR("diveToFile: path = '", path, "'");
 
   if (path[0] == '/') {               // Starting at the root directory?
+    DEBUG_ECHOLN("Starting from ROOT");
+    root.rewind();
     diveDir = &root;
     item_name_adr++;
     DEBUG_ECHOLNPAIR("diveToFile: CWD to root: ", hex_address((void*)diveDir));
     if (update_cwd) workDirDepth = 0; // The cwd can be updated for the benefit of sub-programs
   }
   else
+    DEBUG_ECHOLN("Starting from WorkingDirectory");
     diveDir = &workDir;               // Dive from workDir (as set by the UI)
 
   startDir = diveDir;
@@ -831,12 +974,16 @@ const char* CardReader::diveToFile(const bool update_cwd, SdFile*& diveDir, cons
     strncpy(dosSubdirname, item_name_adr, len);
     dosSubdirname[len] = 0;
 
-    if (echo) SERIAL_ECHOLN(dosSubdirname);
-
     DEBUG_ECHOLNPAIR("diveToFile: sub = ", hex_address((void*)sub));
 
     // Open diveDir (closing first)
     sub->close();
+    #if ENABLED(LONG_FILENAME_HOST_SUPPORT)
+      // Select the folder by name and ensure the DOS8.3 name is used
+      DEBUG_ECHOLNPAIR("Search for folder: ", dosSubdirname);
+      selectByName(*diveDir,dosSubdirname, false) ;
+      if (strlen(filename) > 0 ) strcpy(dosSubdirname,filename);
+    #endif
     if (!sub->open(diveDir, dosSubdirname, O_READ)) {
       openFailed(dosSubdirname);
       item_name_adr = nullptr;
@@ -866,7 +1013,7 @@ const char* CardReader::diveToFile(const bool update_cwd, SdFile*& diveDir, cons
 
     // Next path atom address
     item_name_adr = name_end + 1;
-  }
+  } // end while loop
 
   if (update_cwd) {
     workDir = *diveDir;
@@ -875,7 +1022,23 @@ const char* CardReader::diveToFile(const bool update_cwd, SdFile*& diveDir, cons
     TERN_(SDCARD_SORT_ALPHA, presort());
   }
 
-  return item_name_adr;
+    #if ENABLED(LONG_FILENAME_HOST_SUPPORT)
+    // Select the file by name and ensure the DOS8.3 name is returned
+    if (NewFile) {
+      return item_name_adr; // Expecting the start location of a new file. Nothing else to do here.
+    }else {
+      // Expecting a file that already exists - Search and select
+      diveDir->rewind();
+      DEBUG_ECHOLNPAIR("Search for file: ", item_name_adr);
+      selectByName(*diveDir, item_name_adr, false) ;
+      DEBUG_ECHOLNPAIR("diveToFile: Return String = ", filename);
+      return filename;
+    }
+  #else
+    DEBUG_ECHOLNPAIR("diveToFile: Return String = ", item_name_adr);
+    return item_name_adr;
+  #endif
+
 }
 
 void CardReader::cd(const char * relpath) {
diff --git a/Marlin/src/sd/cardreader.h b/Marlin/src/sd/cardreader.h
index 33645b6531..6a95db298f 100644
--- a/Marlin/src/sd/cardreader.h
+++ b/Marlin/src/sd/cardreader.h
@@ -81,7 +81,7 @@ public:
   static void mount();
   static void release();
   static inline bool isMounted() { return flag.mounted; }
-  static void ls();
+  static void ls(boolean ReturnDOSFileNames,boolean ReturnLongFileNames);
 
   // Handle media insert/remove
   static void manage_media();
@@ -104,7 +104,7 @@ public:
 
   static inline char* longest_filename() { return longFilename[0] ? longFilename : filename; }
   #if ENABLED(LONG_FILENAME_HOST_SUPPORT)
-    static void printLongPath(char * const path);   // Used by M33
+    static void printLongPath(char * const path, boolean PrintLineReturn);   // Used by M33
   #endif
 
   // Working Directory for SD card menu
@@ -135,7 +135,7 @@ public:
   static inline uint8_t percentDone() { return (isFileOpen() && filesize) ? sdpos / ((filesize + 99) / 100) : 0; }
 
   // Helper for open and remove
-  static const char* diveToFile(const bool update_cwd, SdFile*& curDir, const char * const path, const bool echo=false);
+  static const char* diveToFile(const bool update_cwd, SdFile*& curDir, const char * const path, const bool NewFile=false);
 
   #if ENABLED(SDCARD_SORT_ALPHA)
     static void presort();
@@ -273,8 +273,9 @@ private:
   static bool is_dir_or_gcode(const dir_t &p);
   static int countItems(SdFile dir);
   static void selectByIndex(SdFile dir, const uint8_t index);
-  static void selectByName(SdFile dir, const char * const match);
-  static void printListing(SdFile parent, const char * const prepend=nullptr);
+  static void selectByName(SdFile dir, const char * const match, boolean debug=false);
+  static void printListing(SdFile parent, boolean ReturnDOSFileNames, boolean ReturnLongFileNames, const char * const prepend=nullptr);
+  static void printDirListing(SdFile parent, boolean ReturnDOSFileNames, boolean ReturnLongFileNames, const char * const prepend=nullptr);
 
   #if ENABLED(SDCARD_SORT_ALPHA)
     static void flush_presort();