I have two Pi Zeros, both new, and two identical brand new Micro SD Cards.
Having finished the testing phase of my project I started today by downloading the latest version of stretch lite (Version:March 2018 - Release date:2018-03-13 - Kernel version:4.9), validating the download and flashing it onto both SD Cards. This seems to have worked fine, and I booted both pi Zeros from them fine.
I then enabled camera support and rebooted them both.
One booted fine, the other performed a disk validation, then told me the root account was locked, so I had to press enter.
Gave up on the failed boot, reflashed, and again the first boot was fine and the second one was not. Swapped the SDs over, started from scratch on both, and found that it's the Pi causing the problem - but I've no idea why.
How could I find out what the problem is, and what logs would be useful in diagnosing it?