Button test screen
You can get to a button test / debug screen by starting your Evercade (allow it to start, but don’t start any game) and holding down X and Y and the left and right shoulder button. (It might take a few goes)
You should see a screen like this and hear some music.
Firmware update on Mac
Currently the firmware updates for the Evercade are only supported on Windows.
There is a workaround, however, but it takes a little bit of work.
What you need to do is install a Windows Virtual Machine on your Mac.
VirtualBox or VMWare Fusion are 2 popular options to use to do this.
Once you have the Virtual Machine Hypervisor installed you can install windows in it – essentially you will be running Windows from inside your Mac.
There is a nice guide on how to install a Windows on a Mac with VirtualBox here.
Once that’s all working, you can plug in the Evercade and install the firmware update on your Evercade !
Twitter user drgr retro has reported success with this method (my suggestion I might add 😊 ) so it’s been tried and tested.
Linux Firmware Upgrade
Check out this great post that gives really easy instructions for firmware update on Linux: https://fun2code-blog.blogspot.com/2020/07/evercade-flashing-firware-on-linux.html
Atari Lynx Hints and Cheats Book
Turns out there was an internal atari book of hints and cheats for the Lynx. Lots of cool stuff in this one.
Get it here.