diff --git a/hw/AT91SAM/hardware.c b/hw/AT91SAM/hardware.c
index 70f900f..afd2346 100644
--- a/hw/AT91SAM/hardware.c
+++ b/hw/AT91SAM/hardware.c
@@ -372,6 +372,7 @@ void InitADC(void) {
   PollOneADC();
   PollOneADC();
   PollOneADC();
+  PollOneADC();
 }
 
 // poll one adc channel every 25ms
diff --git a/hw/AT91SAM/hardware.h b/hw/AT91SAM/hardware.h
index e40d40a..a30316f 100644
--- a/hw/AT91SAM/hardware.h
+++ b/hw/AT91SAM/hardware.h
@@ -94,6 +94,9 @@
 #define VIDEO_SD_DISABLE_VAR (*(uint8_t*)0x0020FF15)
 #define VIDEO_YPBPR_VAR      (*(uint8_t*)0x0020FF16)
 
+#define USB_BOOT_VALUE       0x8007F007
+#define USB_BOOT_VAR         (*(int*)0x0020FF18)
+
 #define SECTOR_BUFFER_SIZE   4096
 
 char mmc_inserted(void);
diff --git a/main.c b/main.c
index 9e4d34a..e080110 100644
--- a/main.c
+++ b/main.c
@@ -106,6 +106,19 @@ void HandleFpga(void) {
 
 extern void inserttestfloppy();
 
+#ifdef USB_STORAGE
+int GetUSBStorageDevices()
+{
+  uint32_t to = GetTimer(2000);
+
+  // poll usb 2 seconds or until a mass storage device becomes ready
+  while(!storage_devices && !CheckTimer(to))
+    usb_poll();
+
+  return storage_devices;
+}
+#endif
+
 int main(void)
 {
     uint8_t mmc_ok = 0;
@@ -133,30 +146,36 @@ int main(void)
     if(MMC_Init()) mmc_ok = 1;
     else           spi_fast();
 
-    // TODO: If MMC fails try to wait for USB storage
-
     iprintf("spiclk: %u MHz\r", GetSPICLK());
 
     usb_init();
 
-    // mmc init failed, try to wait for usb
-    if(!mmc_ok) {
-      uint32_t to = GetTimer(2000);
+    InitADC();
 
 #ifdef USB_STORAGE
-      // poll usb 2 seconds or until a mass storage device becomes ready
-      while(!storage_devices && !CheckTimer(to)) 
-	usb_poll();
+    if(UserButton()) USB_BOOT_VAR = (USB_BOOT_VAR == USB_BOOT_VALUE) ? 0 : USB_BOOT_VALUE;
 
-      // no usb storage device after 2 seconds ...
-      if(!storage_devices)
-        FatalError(1);	
-
-      fat_switch_to_usb();  // redirect file io to usb
-#else
-      FatalError(1);	
+    if(USB_BOOT_VAR == USB_BOOT_VALUE)
+      if (!GetUSBStorageDevices()) {
+        if(!mmc_ok)
+          FatalError(1);
+      } else
+        fat_switch_to_usb();  // redirect file io to usb
+    else {
 #endif
+      if(!mmc_ok) {
+#ifdef USB_STORAGE
+        if(!GetUSBStorageDevices())
+          FatalError(1);
+
+        fat_switch_to_usb();  // redirect file io to usb
+#else
+        FatalError(1);
+#endif
+      }
+#ifdef USB_STORAGE
     }
+#endif
 
     if (!FindDrive())
         FatalError(2);
diff --git a/usb/hub.c b/usb/hub.c
index c821b1d..8204a9c 100644
--- a/usb/hub.c
+++ b/usb/hub.c
@@ -33,7 +33,6 @@ static uint8_t usb_hub_get_port_status(usb_device_t *dev, uint8_t port, uint16_t
 }
 
 static uint8_t usb_hub_parse_conf(usb_device_t *dev, uint8_t conf, uint16_t len, ep_t *pep) {
-  usb_storage_info_t *info = &(dev->storage_info);
   uint8_t rcode;
   bool is_good_interface = false;
 
diff --git a/usb/storage.c b/usb/storage.c
index 8b74f09..ce54d09 100644
--- a/usb/storage.c
+++ b/usb/storage.c
@@ -2,6 +2,7 @@
 // storage.c
 //
 
+#ifdef USB_STORAGE
 #include <stdio.h>
 #include <string.h>
 
@@ -497,3 +498,4 @@ unsigned int usb_host_storage_capacity() {
 
 const usb_device_class_config_t usb_storage_class = {
   usb_storage_init, usb_storage_release, usb_storage_poll };  
+#endif
diff --git a/user_io.c b/user_io.c
index b699042..c6d618c 100644
--- a/user_io.c
+++ b/user_io.c
@@ -150,8 +150,6 @@ void user_io_init() {
 	// mark remap table as unused
 	memset(key_remap_table, 0, sizeof(key_remap_table));
 
-	InitADC();
-
 	if(MenuButton()) DEBUG_MODE_VAR = DEBUG_MODE ? 0 : DEBUG_MODE_VALUE;
 	iprintf("debug_mode = %d\n", DEBUG_MODE);