diff --git a/firmware/common/dir_uncached.c b/firmware/common/dir_uncached.c
index e4c4397..5d43166 100644
--- a/firmware/common/dir_uncached.c
+++ b/firmware/common/dir_uncached.c
@@ -36,7 +36,7 @@
 
 static DIR_UNCACHED opendirs[MAX_OPEN_DIRS];
 
-#ifdef HAVE_HOTSWAP
+#if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK))
 // release all dir handles on a given volume "by force", to avoid leaks
 int release_dirs(int volume)
 {
@@ -57,7 +57,7 @@ int release_dirs(int volume)
     }
     return closed; /* return how many we did */
 }
-#endif /* #ifdef HAVE_HOTSWAP */
+#endif /* #if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK)) */
 
 DIR_UNCACHED* opendir_uncached(const char* name)
 {
diff --git a/firmware/common/disk.c b/firmware/common/disk.c
index 6be9b47..ee7d34c 100644
--- a/firmware/common/disk.c
+++ b/firmware/common/disk.c
@@ -23,7 +23,7 @@
 #include "storage.h"
 #include "debug.h"
 #include "fat.h"
-#ifdef HAVE_HOTSWAP
+#if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK))
 #include "dir.h" /* for release_dirs() */
 #include "file.h" /* for release_files() */
 #endif
@@ -235,12 +235,14 @@ int disk_mount(int drive)
     return mounted;
 }
 
-#ifdef HAVE_HOTSWAP
+#if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK))
 int disk_unmount(int drive)
 {
     int unmounted = 0;
     int i;
+#ifdef HAVE_HOTSWAP
     mutex_lock(&disk_mutex);
+#endif
     for (i=0; i<NUM_VOLUMES; i++)
     {
         if (vol_drive[i] == drive)
@@ -252,8 +254,31 @@ int disk_unmount(int drive)
             fat_unmount(i, false);
         }
     }
+#ifdef HAVE_HOTSWAP
     mutex_unlock(&disk_mutex);
+#endif
+
+    return unmounted;
+}
+#endif /* #if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK)) */
+
+#if defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK))
+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
+        if (storage_present(i))
+#endif
+            unmounted += disk_unmount(i);
+    }
 
     return unmounted;
+#endif  /* HAVE_MULTIDRIVE */
 }
-#endif /* #ifdef HAVE_HOTSWAP */
+#endif /* defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK)) */
diff --git a/firmware/common/file.c b/firmware/common/file.c
index da85846..0278444 100644
--- a/firmware/common/file.c
+++ b/firmware/common/file.c
@@ -793,7 +793,7 @@ off_t filesize(int fd)
 }
 
 
-#ifdef HAVE_HOTSWAP
+#if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK))
 /* release all file handles on a given volume "by force", to avoid leaks */
 int release_files(int volume)
 {
@@ -814,4 +814,4 @@ int release_files(int volume)
     }
     return closed; /* return how many we did */
 }
-#endif /* #ifdef HAVE_HOTSWAP */
+#endif /* #if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK)) */
diff --git a/firmware/drivers/fat.c b/firmware/drivers/fat.c
index cff11d2..70ffb7f 100644
--- a/firmware/drivers/fat.c
+++ b/firmware/drivers/fat.c
@@ -479,7 +479,7 @@ int fat_mount(IF_MV2(int volume,) IF_MD2(int drive,) long startsector)
     return 0;
 }
 
-#ifdef HAVE_HOTSWAP
+#if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK))
 int fat_unmount(int volume, bool flush)
 {
     int rc;
@@ -518,7 +518,7 @@ int fat_unmount(int volume, bool flush)
 #endif
     return rc;
 }
-#endif /* #ifdef HAVE_HOTSWAP */
+#endif /* #if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK)) */
 
 void fat_recalc_free(IF_MV_NONVOID(int volume))
 {
diff --git a/firmware/export/disk.h b/firmware/export/disk.h
index db722a8..347d8b4 100644
--- a/firmware/export/disk.h
+++ b/firmware/export/disk.h
@@ -41,6 +41,7 @@ struct partinfo* disk_partinfo(int partition);
 void disk_init_subsystem(void); /* Initialises mutexes */
 int disk_mount_all(void); /* returns the # of successful mounts */
 int disk_mount(int drive);
+int disk_unmount_all(void);
 int disk_unmount(int drive);
 
 /* The number of 512-byte sectors in a "logical" sector. Needed for ipod 5.5G */
diff --git a/firmware/usb.c b/firmware/usb.c
index 9eaf201..6309c14 100644
--- a/firmware/usb.c
+++ b/firmware/usb.c
@@ -131,6 +131,7 @@ static inline void usb_slave_mode(bool on)
 #ifdef HAVE_PRIORITY_SCHEDULING
         thread_set_priority(THREAD_ID_CURRENT, PRIORITY_REALTIME);
 #endif
+        disk_unmount_all();
         usb_attach();
     }
     else /* usb_state == USB_INSERTED (only!) */
@@ -172,6 +173,7 @@ static inline void usb_slave_mode(bool on)
     if(on)
     {
         DEBUGF("Entering USB slave mode\n");
+        disk_unmount_all();
         storage_soft_reset();
         storage_init();
         storage_enable(false);