Yeah, the way it seems to work though is that when you reflash the MiST, you have to go with the firmware.bin from 2013. The upgraded firmware files require themselves to be flashed from an already-working board.

We'll see if one of their recommended MicroSD cards makes a difference. It'll arrive tomorrow, I think.

Ok so, setting up the MiST seemed really complicated to me at first. It sounds like you have a slightly newer model than I have (mine uses standard size SD cards) but most of the logic still applies.

There are firmwares and cores. There are different cores for each system, but only one firmware, and sometimes the cores don't work if they're not the same version as the firmware.

To keep things simple, I ended up using multiple SD cards: one for the Amiga, one for the Atari ST, and one for the Atari 8 bit. Note that when I updated to a certain firmware, the Atari ST core quit working on my television so I had to change over to a monitor. Now that I'm using a computer monitor, the ST core works but the 8 bit one doesn't display.

To get it working, I would download the latest firmware and flash that. Then just copy one of the cores (the Amiga seems to be the most compatible) and see if you can get that working first.

Was it a mouse or a trackball?

I got the MiST! Booted up some Amiga stuff!

I went to plug in a mouse. It will no longer boot from the MicroSD card. I've tried reformatting the card and going from the Amiga stuff to the Atari ST stuff but no dice. I get three blinking (red) lights, which I can find the error code for but that does not help me.

It's got to be really fucked if it can no longer read from the MicroSD card at ALL. Nnnngh.