[error] fifo_full

FIFO_FULL means that there was more data coming in to Espruino than it could handle.

More than likely it's due to:

• Code that outputs a lot of data to the console - Puck.js waits for the data to send, but during that time data is coming in.
  
• Code that keeps Puck.js busy for a long time - especially if that code is written so it runs as the code is being uploaded
  
• Lots of data coming in to Espruino, for example setWatch on a pin that changes state very often.
  
  

In this case given the jsble_exec_pending error it looks like it might be some BLE issues - maybe using setScan for advertising data but taking a long time to process it?

Are you able to post up you code? Also when does the error occur? At upload time, or at some point later on?