There are three ways to factory reset the Nano, and they all do the same thing in the end: they wipe the device back to how it left the factory. You might do this to clear out a full set of old flights, to undo settings changes you no longer want, or simply to hand the altimeter on to someone else with a clean slate. This page covers all three methods and what to expect once a reset is under way.
This is the quickest method and the only one that needs no computer at all. It works whether the Nano is in flight mode or in USB mode. Press and hold the boot button, and the status LED gives you a clear sequence of feedback as you hold, so you always know how far along you are.
After about three seconds the LED shows a brief white flash. Keep holding and it begins to blink orange, which is the warning stage telling you a reset is coming. At around nine seconds the LED turns solid red and the reset begins on its own. You do not need to keep holding once it goes red. If you change your mind at any point before the red light, simply let go of the button and nothing is erased.
Re-applying the firmware with our online firmware update tool also returns the Nano to a clean state, so it doubles as a reliable way to reset the device. This is a good choice if you want to be certain the altimeter is running the latest firmware at the same time. Connect the Nano to your computer with a USB cable, open the firmware update tool in your browser, and follow the steps it shows you to flash the firmware.
Once the firmware has been written, the Nano starts up fresh and rebuilds its default files exactly as it would after any other reset.
The third method uses nothing more than a plain text editor, so it works on any computer without special software. Connect the Nano with a USB cable and it appears as a small USB drive. Open the file named device_settings.txt on that drive, find the line for factoryreset, and change its value from 0 to 1.
Save the file, eject the drive safely, then power the Nano off and on again, or unplug and replug it. On its next power up the Nano sees the changed value and performs the reset for you. Because the file system is rewritten during the reset, the fresh device_settings.txt that replaces it has factoryreset back at 0, so it will not loop or reset a second time.
Whichever method you use, the reset itself behaves the same way. The Nano clears its settings, reformats its internal file space, and writes out a fresh set of default files, including a new device_settings.txt with all values back at their factory defaults.
While it does this the Nano restarts itself a few times, and the whole process takes around twenty seconds from start to finish. This is completely normal. Give it time to settle and finish on its own before you unplug it or expect it to reappear as a USB drive. Once it has finished you have a clean device, ready to record again.