I noticed that the AutoPi TMU 3rd edition says that it is:
The AutoPi TMU Pi3 ships with the Raspberry Pi3 Model A+, but has been designed for the future. This means that it is easily upgradeable to the Raspberry Pi 4, if you need even additional processing power.
I guess I was wondering how this worked exactly. Do I just buy a Raspberry Pi 4, take it apart, throw the new one in, put the SD card in the new one and bada-bing bada-boom I’m done. Everything will just fit, and all the things will be aligned and I don’t even need a new face plate? I’m concerned about the about how the chassis will work with the Raspberry Pi 4, since it looks like this is a model A, but there is no Raspberry Pi 4, model A.
So it does fit in there, but the current images aren’t compatible with the Raspberry Pi 4, and so it doesn’t boot. I was able to put in a Raspberry Pi Model 3B+ to replace the Model 3A.
I was having some weirdness, since the hostname and a bunch of configuration is based on system identifiers like MAC address etc, and I think only setup during the initial boot, so since these changed I was noticing some weirdness. I ended up reflashing it and it seems to be stable now.