Ender 3 Firmware Update
From Rabbi Blog
First time firmware update and first time arduino usage for anything other than powering a robotic car.
I found a couple of videos and articles, this article was the most overall helpful (remember to remove the connection to the arduino after flashing the bootloader) and this article has a troubleshooting section that was helpful when I had communication issues with the Ender 3.
I had borrowed a Elegoo Uno Arduino from a friend and for future reference am including the pin-out.
In regards to the communication problem, I had to select the correct board type which wasn't intuitive for the first run.
So we're running Marlin 1.1.9 now. Maybe OctoPrint next?
Notes and references
So the only other upgrade (which I'm currently looking into), not to de-focus you (but something you may want later on). The stock board does not allow for easy firmware upgrading, you need an arduino board and some wires. Ideally you want to run something open source like marlin which adds thermal runaway protection, things like octoprint (remote monitoring, adding webcams, etc). For a while now you either had to buy a bootloader, or replace the board with something completely different (which requires re-routing wires, swapping out connectors, etc.). A new board came out last month that is a direct drop-in replacement, comes with Marlin (but you can upgrade firmware with the sd card), adds 32-bit cpu.. it's only $20. 32-bit board means way smoother servo control, which greatly quiets down the motors. Also allows you to run optionally higher torque motors, let's you run modded firmware like klipper. I've seen ender3's go from 40mm/sec print speed, to 150+mm/sec print speed and retain most of it's quality