Index: firmware/common/disk.c
===================================================================
--- firmware/common/disk.c  (revision 29021)
+++ firmware/common/disk.c  (working copy)
@@ -263,19 +263,23 @@

 int disk_unmount_all(void)
 {
-#ifndef HAVE_MULTIDRIVE
-    return disk_unmount(0);
-#else  /* HAVE_MULTIDRIVE */
     int unmounted = 0;
     int i;
-    for (i = 0; i < NUM_DRIVES; i++)
+#ifdef HAVE_HOTSWAP
+    mutex_lock(&disk_mutex);
+#endif
+    for (i=0; i<NUM_VOLUMES; i++)
     {
+        if(vol_drive[i] >= 0)
+        {
+            vol_drive[i] = -1; /* mark unused */
+            unmounted++;
+            release_files(i);
+            release_dirs(i);
+            fat_unmount(i, true);
+        }
+    }
 #ifdef HAVE_HOTSWAP
-        if (storage_present(i))
+    mutex_unlock(&disk_mutex);
 #endif
-            unmounted += disk_unmount(i);
-    }

     return unmounted;
-#endif  /* HAVE_MULTIDRIVE */
 }