I've just finished my first proffieboard 2.2 build. I've followed the programming instructions as set out here
Proffieboard V2 and here
ProffieOS.
I've got the config set up to run an RGrB tri-cree, with a single button, and a single RGBW accent pixel. All the components are wired up using the default pads suggested by the Configurator, with the config file it generated copied and pasted over. Everything was compiled and uploaded without problems using the Arduino IDE 1.8.9 in Ubuntu 16:04.
So, I turned the saber on, there was a flash of blue from the LED, and it immediately turned itself off. I turn it back on, it makes a sparking sound, and mumbles LOW POWER. I checked the battery with my multimeter, 3.5V. Not that low for an 18650, but I might as well charge it. I do that. the battery is currently sitting at 4.18v. I turn it on, same story: a spark sound, and a low power warning.
Obviously, something is wrong, but as this is my first Proffieboard, I don't know what.