If I remember correctly, Firmware 2.1.0 stores log files in a subdirectory named ‘LOGS’ whereas previous versions store log files in the root directory. I suspect the issue you encountered may have to do with creating the LOGS folder for the first time, and deleting it when it doesn’t exist. I will check if this is a firmware bug. But I assume after the first log file writes it should be ok. If the issue persists, I would recommend taking out the microSD card and reformatting it.