Keyboard emulation in BIOS

Firmware
1

I’m working on a project to hold a keyboard key combination to launch the macOS recovery partition or boot screen. Keyboard works great when the computer is already booted (except that mac says the keyboard couldn’t be identified when it actually works fine). The problem is that it never registers while the computer is turning on and just does normal boot.

Then I found Bootkeyboard that claims to work in BIOS. Is this just something that cannot be done on Particle? And also why is it even different technically?

2

I’m actually trying to do something very similar with entering the boot selection screen. Have you tried powering the device from battery or a powered USB hub and then plug it in so that it doesn’t have to boot? I wanted to try that but I don’t have either.

Looks like the goal is to enable HID_BOOT_PROTOCOL