6 You should see internal battery. Using small flat screwdriver gently push metal retainer
clip outward until it releases battery.
7 Replace with fresh battery. Insert it from plastic end opposite to metal clip first, and then
press down until retainer clip clicks holding it in place.
Upgrading Firmware
Removing maintenance door will also allow you access to the FTDI programming interface. You
will need a 5V USB FTDI adapter board or cable (you can get one on Sparkfun or eBay). Make
sure you unplug external power first. FTDI will provide power to the clock from your computer
via USB. Please take care of plugging FTDI adapter correctly. Usually it means facing up (as
show on the picture). Just look and match writing next to the pins (i.e. DTR on the far left,
Ground on the far right).
There are basically two way to upgrade firmware, a simplified and advanced.
