After creating the MQTT broker on a Raspberry Pi Zero W via SSH, I now cannot interact with the code, eg, to shutdown. What could be the reason, and is it safe to shut it down cold? I did this with another zero and I think I messed up the EEPROM.
Hello Jack, did you enable SSH in your OS installation?
After the flash process is completed, open your microSD card and you should see something similar to the image below:
You must enable SSH communication, so that you can establish a communication with your Pi.
To do that, go to this link https://drive.google.com/open?id=0B_BzxRImIcd-SWE2NVNPT1FycFE and download a blank file called ssh by click the Download button.
You should have the ssh file (that has no extension) in your Downloads folder.
Move the ssh file to the microSD card as shown below: