I pressed “Update Firmware,” selected “Choose a local firmware build,” and selected the one you linked to, at Keyboardio/Model100/default.bin.
I pressed “Update” and the left column of the Model 100 flashed green, and I got a “Firmware flashed successfully” message with a green light on the Model100.
But even so, Chrysalis still does not recognize the Model 100 - unless I unplug and hold down the prog key again, and then it asks me to update firmware again.
Oh, right. Apologies, this isn’t going to be a firmware issue, nor a Chrysalis one. Chrysalis communicates with the keyboard over USB serial, and for Win7, that might likely require a special driver. You might have some success with Zadig, that’s the one recommended by node-usb. I never managed to make it work, however, so I’m afraid you’re on your own here.
Win7 might have drivers for those, as they predate it’s end of life, while the Model100 does not. I have no idea why the Model01 and Atreus might work, but the Model 100 does not. I never managed to make the former two work either, neither on Win7, nor Win8.