diff --git a/Marlin/src/sd/SdBaseFile.cpp b/Marlin/src/sd/SdBaseFile.cpp
index 48ee94780e..a40f20c4f2 100644
--- a/Marlin/src/sd/SdBaseFile.cpp
+++ b/Marlin/src/sd/SdBaseFile.cpp
@@ -1122,47 +1122,45 @@ int8_t SdBaseFile::readDir(dir_t* dir, char* longFilename) {
       }
     }
 
-    // Return if normal file or subdirectory
-    if (DIR_IS_FILE_OR_SUBDIR(dir)) {
-      #if ENABLED(UTF_FILENAME_SUPPORT)
-        if (longFilename) {
-          // Convert filename from utf-16 to utf-8 as Marlin expects
-          #if LONG_FILENAME_CHARSIZE > 2
-            // Add warning for developers for currently not supported 3-byte cases (Conversion series of 2-byte
-            // codepoints to 3-byte in-place will break the rest of filename)
-            #error "Currently filename re-encoding is done in-place. It may break the remaining chars to use 3-byte codepoints."
-          #endif
-          uint16_t currentPos = 0;
+    #if ENABLED(UTF_FILENAME_SUPPORT)
+      // Return if normal file or subdirectory
+      if (DIR_IS_FILE_OR_SUBDIR(dir)) {
+        // Convert filename from utf-16 to utf-8 as Marlin expects
+        #if LONG_FILENAME_CHARSIZE > 2
+          // Add warning for developers for currently not supported 3-byte cases (Conversion series of 2-byte
+          // codepoints to 3-byte in-place will break the rest of filename)
+          #error "Currently filename re-encoding is done in-place. It may break the remaining chars to use 3-byte codepoints."
+        #endif
 
-          LOOP_L_N(i, (LONG_FILENAME_LENGTH / 2)) {
-            uint16_t idx = i * 2; // This is fixed as FAT LFN always contain UTF-16LE encoding
+        // Is there a long filename to decode?
+        if (!longFilename) return n;  // sizeof(dir_t)
 
-            uint16_t utf16_ch = longFilename[idx] | (longFilename[idx + 1] << 8);
-            if (0xD800 == (utf16_ch & 0xF800))                                    // Surrogate pair - encode as '_'
-              longFilename[currentPos++] = '_';
-            else if (0 == (utf16_ch & 0xFF80))                                    // Encode as 1-byte utf-8 char
-              longFilename[currentPos++] = utf16_ch & 0x007F;
-            else if (0 == (utf16_ch & 0xF800)) {                                  // Encode as 2-byte utf-8 char
-              longFilename[currentPos++] = 0xC0 | ((utf16_ch >> 6) & 0x1F);
-              longFilename[currentPos++] = 0x80 | (utf16_ch & 0x3F);
-            }
-            else {
-              #if LONG_FILENAME_CHARSIZE > 2                                      // Encode as 3-byte utf-8 char
-                longFilename[currentPos++] = 0xE0 | ((utf16_ch >> 12) & 0x0F);
-                longFilename[currentPos++] = 0xC0 | ((utf16_ch >> 6) & 0x3F);
-                longFilename[currentPos++] = 0xC0 | (utf16_ch & 0x3F);
-              #else                                                               // Encode as '_'
-                longFilename[currentPos++] = '_';
-              #endif
-            }
-
-            if (0 == utf16_ch) break; // End of filename
+        // Reset n to the start of the long name
+        n = 0;
+        for (uint16_t idx = 0; idx < (LONG_FILENAME_LENGTH) / 2; idx += 2) {    // idx is fixed since FAT LFN always contains UTF-16LE encoding
+          uint16_t utf16_ch = longFilename[idx] | (longFilename[idx + 1] << 8);
+          if (0xD800 == (utf16_ch & 0xF800))                                    // Surrogate pair - encode as '_'
+            longFilename[n++] = '_';
+          else if (0 == (utf16_ch & 0xFF80))                                    // Encode as 1-byte UTF-8 char
+            longFilename[n++] = utf16_ch & 0x007F;
+          else if (0 == (utf16_ch & 0xF800)) {                                  // Encode as 2-byte UTF-8 char
+            longFilename[n++] = 0xC0 | ((utf16_ch >> 6) & 0x1F);
+            longFilename[n++] = 0x80 | ( utf16_ch       & 0x3F);
           }
-          n = currentPos;
+          else {
+            #if LONG_FILENAME_CHARSIZE > 2                                      // Encode as 3-byte UTF-8 char
+              longFilename[n++] = 0xE0 | ((utf16_ch >> 12) & 0x0F);
+              longFilename[n++] = 0xC0 | ((utf16_ch >>  6) & 0x3F);
+              longFilename[n++] = 0xC0 | ( utf16_ch        & 0x3F);
+            #else                                                               // Encode as '_'
+              longFilename[n++] = '_';
+            #endif
+          }
+          if (0 == utf16_ch) break; // End of filename
         }
-      #endif
-      return n;
-    }
+        return n;
+      }
+    #endif
   }
 }