The past weeks I ran into problems with esptool that irked me, because apparently no one else had them. I would upload sketches through platformio or on the command line, and each and every time the upload would fail – regardless whether it was an ESP32 board or an old trusty NodeMCU, and regardless whether it was the esptool that comes with platformio or the one installed via pip.

It would always work out like this: I’d start the upload, and then an error like this would come up:

Writing at 0x00018000... (35 %)Traceback (most recent call last):
File "/usr/local/lib/python3.5/dist-packages/serial/serialposix.py", line 501, in read
'device reports readiness to read but returned no data '
serial.serialutil.SerialException: device reports readiness to read but returned no data (device disconnected or multiple access on port?)
[…]
raise SerialException('read failed: {}'.format(e))
serial.serialutil.SerialException: read failed: device reports readiness to read but returned no data (device disconnected or multiple access on port?)


It wasn’t until I sat at my desk, looking at the last line of the error and looking at the flight case full of DMX lights that it hit me. I had installed OLA on my machine, and olad would start automatically to control DMX fixtures via USB adapter.

Welp.

Saving this for others that might run into the same problem. Kill olad and disable olad autostart.