diff --git a/features/filesystem/fat/FATFileSystem.cpp b/features/filesystem/fat/FATFileSystem.cpp
index 2413e03274..05e4849609 100644
--- a/features/filesystem/fat/FATFileSystem.cpp
+++ b/features/filesystem/fat/FATFileSystem.cpp
@@ -35,48 +35,39 @@
 static int fat_error_remap(FRESULT res)
 {
     switch(res) {
-        case FR_OK:                   // (0) Succeeded
-            return 0;
-        case FR_DISK_ERR:             // (1) A hard error occurred in the low level disk I/O layer
-            return -EIO;
-        case FR_INT_ERR:              // (2) Assertion failed
-            return -1;
-        case FR_NOT_READY:            // (3) The physical drive cannot work
-            return -EIO;
-        case FR_NO_FILE:              // (4) Could not find the file
-            return -ENOENT;
-        case FR_NO_PATH:              // (5) Could not find the path
-            return -ENOTDIR;
-        case FR_INVALID_NAME:         // (6) The path name format is invalid
-            return -EINVAL;
-        case FR_DENIED:               // (7) Access denied due to prohibited access or directory full
-            return -EACCES;
-        case FR_EXIST:                // (8) Access denied due to prohibited access
-            return -EEXIST;
-        case FR_INVALID_OBJECT:       // (9) The file/directory object is invalid
+        case FR_OK:                     /* (0) Succeeded */
+            return 0;                   /* no error */
+        case FR_DISK_ERR:               /* (1) A hard error occurred in the low level disk I/O layer */
+        case FR_NOT_READY:              /* (3) The physical drive cannot work */
+            return -EIO;                /* I/O error */
+        case FR_NO_FILE:                /* (4) Could not find the file */
+        case FR_NO_PATH:                /* (5) Could not find the path */
+        case FR_INVALID_NAME:           /* (6) The path name format is invalid */
+        case FR_INVALID_DRIVE:          /* (11) The logical drive number is invalid */
+        case FR_NO_FILESYSTEM:          /* (13) There is no valid FAT volume */
+            return -ENOENT;             /* No such file or directory */
+        case FR_DENIED:                 /* (7) Access denied due to prohibited access or directory full */
+            return -EACCES;             /* Permission denied */
+        case FR_EXIST:                  /* (8) Access denied due to prohibited access */
+            return -EEXIST;             /* File exists */
+        case FR_WRITE_PROTECTED:        /* (10) The physical drive is write protected */
+        case FR_LOCKED:                 /* (16) The operation is rejected according to the file sharing policy */
+            return -EACCES;             /* Permission denied */
+        case FR_INVALID_OBJECT:         /* (9) The file/directory object is invalid */
+            return -EFAULT;             /* Bad address */
+        case FR_NOT_ENABLED:            /* (12) The volume has no work area */
+            return -ENXIO;              /* No such device or address */
+        case FR_NOT_ENOUGH_CORE:        /* (17) LFN working buffer could not be allocated */
+            return -ENOMEM;             /* Not enough space */
+        case FR_TOO_MANY_OPEN_FILES:    /* (18) Number of open files > _FS_LOCK */
+            return -ENFILE;             /* Too many open files in system */
+        case FR_INVALID_PARAMETER:      /* (19) Given parameter is invalid */
+            return -ENOEXEC;            /* Exec format error */
+        case FR_INT_ERR:                /* (2) Assertion failed */
+        case FR_MKFS_ABORTED:           /* (14) The f_mkfs() aborted due to any parameter error */
+        case FR_TIMEOUT:                /* (15) Could not get a grant to access the volume within defined period */
+        default:                        /* Bad file number */
             return -EBADF;
-        case FR_WRITE_PROTECTED:      // (10) The physical drive is write protected
-            return -EACCES;
-        case FR_INVALID_DRIVE:        // (11) The logical drive number is invalid
-            return -ENODEV;
-        case FR_NOT_ENABLED:          // (12) The volume has no work area
-            return -ENODEV;
-        case FR_NO_FILESYSTEM:        // (13) There is no valid FAT volume
-            return -EINVAL;
-        case FR_MKFS_ABORTED:         // (14) The f_mkfs() aborted due to any problem
-            return -EIO;
-        case FR_TIMEOUT:              // (15) Could not get a grant to access the volume within defined period
-            return -ETIMEDOUT;
-        case FR_LOCKED:               // (16) The operation is rejected according to the file sharing policy
-            return -EBUSY;
-        case FR_NOT_ENOUGH_CORE:      // (17) LFN working buffer could not be allocated
-            return -ENOMEM;
-        case FR_TOO_MANY_OPEN_FILES:  // (18) Number of open files > FF_FS_LOCK
-            return -ENFILE;
-        case FR_INVALID_PARAMETER:    // (19) Given parameter is invalid
-            return -EINVAL;
-        default:
-            return -res;
     }
 }