It does not work with ZXbaremulator about stm32-ps2-usb-converter HOT 2 CLOSED

Hi, I'm happy someone finds it useful :-)

Regarding the boot descriptor: I'm assuming that refers to the HID descriptor being boot-mode compatible. The keyboard descriptor I've implemented should be compatible. You can find the descriptor in usb.c:42.

The issue that it is not working might be that emulator initialization sequence expects the keyboard to be plugged in and ready on power on and doesn't support plugging the device in (or the device getting ready) after the system was powered up. I don't known how long the software waits before talking to the device. This might be a timing issue.

from stm32-ps2-usb-converter.

You're welcome! :)
I'm going to embed Raspberry Pi Zero W into the PS2 keyboard (the keyboard is small and looks pretty cool), so I will reuse your project there - it works pretty smooth with Raspbian OS). 

But I was now able to get it working with ZXBaremulator. The author suggested to add a parameter usbpowerdelay=2000 in cmdline.txt file. It slowed down the boot by two seconds but it did not help. Even with 5 seconds ZXbaremulator can't detect the keyboard.

If you're interesting and you have RPi 2/3 at home, you can try ZXbaremulator - it is a really nice piece of retro-engineering, although the author has lost his motivation to continue its development.

from stm32-ps2-usb-converter.