Today, my nine-year-old daughter and I upgraded our little mini quad (7" across), which we hadn't flown in a while.
Here's what we did:
1. Soldered the headers onto a new ArduPilot Mega 2560 board and installed it into the quad. (Replacing the 1280 that was there).
2. In the past we couldn't find the small 4x2.5 propellers in both a pusher and puller style, so we compensated for this by tilting the motors 8 degrees. We recently received a shipment of the proper pushers and pullers, so we installed those and re-positioned the motors so they were straight up.
3. In the past we used the CLI and the "Indoor" code. This time, we used the Mission Planner to load the current standard code (AC 2.0.39b), and then we re-configured as per the wiki.
After completing our upgrades, we ran through the normal tests and everything checked out so we took it out for a flight. It immediately flew absolutely beautifully. Very stable and responsive. This was by far the most stable we had ever seen this mini quad fly (or any of our quads). Awesome! Well done, DIY Drones team! :)
Here are some pictures of my daughter soldering the header pins on the new ArduPilot Mega board and then installing it into the quad. I've also included a picture of the finished upgraded quad, which we call "The Black Hornet."