Please connect the update tool to your Crossbow tracker.
Insert the USB plug to your windows PC.
Install the driver for USB-TTL if necessary:
http://www.myflydream.com/inc/lib/download/download.php?DId=30
download the MFD FW & update tool (you need .Net 4.0 framework to use it)
http://www.myflydream.com/inc/lib/download/download.php?DId=61
>>> Choose "38400" baudrate for Crossbow <<<
>>>You need to power on your Crossbow to update firmwares <<<