I’d like to upgrade mine too but there doesn’t seem to exist a ‘Programming the OpenEVSE for Dummies’ documentation available anywhere.
I’m assuming I just need some (yet to be determined) software on my Linux or Win10 laptop, that board you highlighted and a USB cable to join the two, connect to a disconnected OpenEVSE, point the software to the firmware location and hit upload or something.
However, the wife won’t be pleased if I brick it and she can’t charge her beloved Zoe.