Flashing AirOS from UniFi on a PicoStation M2

I was having a tough time figuring out how to downgrade the firmware of my AP that I flashed with UniFi.  After some googling around, I stumbled upon this thread that got me headed in the right direction.

In short, here are the steps:

1. Confirm you have no devices assigned to 192.168.1.20.  If you do, move them.
2. SSH into your AP and run upgrade http://www.voyagerwireless.com/ubnt/UniFi2AirOS.bin
3. Wait 60 seconds, unplug the ethernet cable.
4. Now put the AP into TFTP mode by pressing and holding the reset button while you insert the ethernet cable.  After you hold the button for about 10 seconds and see the lights flashing in pairs, you are in TFTP mode.  Confirm you can ping it at 192.168.1.20.
5. Download the latest firmware for the device form Ubiquiti and save it as firmware.bin.  Make sure you download it for the M2 model and not just the second model.
6. Open terminal in the folder where you’ve saved the firmware file, and send the file over TFTP using the following
7. YAML

   $ tftp 192.168.1.20

   1	$ tftp 192.168.1.20

8. YAML

   tftp> binary

   1	tftp> binary

9. YAML

   tftp> put firmware.bin

   1	tftp> put firmware.bin

10. YAML

    Sent 7698035 bytes in 6.2 seconds

    1	Sent 7698035 bytes in 6.2 seconds

11. YAML

    tftp> quit

    1	tftp> quit

12.