Sansa E200v1 Bootloader ensure USB unplug is detected

Change-Id: Ibec5bf5e0f7a518fafc7b9fb8b95d420ef4ddfc0

bootloader/main-pp.c

···
 
             usb = USB_HANDLED;
             usb_acknowledge(SYS_USB_CONNECTED_ACK);
+#if defined(SANSA_E200) && defined(HAVE_BOOTLOADER_USB_MODE)
+            /* E200 misses unplug randomly
+               probably fine for other targets too but needs tested */
+            while (usb_wait_for_disconnect_w_tmo(&q, HZ * 5) > 0)
+            {
+                /* timeout */
+                if (!usb_plugged())
+                    break;
+            }
+#else
             usb_wait_for_disconnect(&q);
+#endif
             break;
         }