Proffie Stopped Responding, Serial Monitor

I am having issues with a few proffie boards. I am reprogramming some and have a 50% success rate so far on 8 total boards. I am unable to get the serial monitor to work. The boards that do not operate worked before downloading an updated code. However, the code does not seem to be the issue, since 4 of the 8 boards worked fine after download. Any help is appreciated. Thank you.

Is it a v3.9 board?
If you open serial monitor (and it’s blank), try going to Arduino menu Tools>Port and reselect the Proffieboard (even if it’s already selected).
Does that make Serial Monitor refresh and work?

Need a lot more information:

  1. Is it a V2 or V3 board?
  2. What version of ProffieOS are you using?
  3. What version of the arduino-proffieboard plugin?
  4. Post your config file (is it the same for all the boards?)
  5. Does it work better (or at least all the same) if you remove the SD card?