If you find out that your mechanical Ducky Zero (DK 2108) keyboard doesn’t work anymore once you upgraded your mac to Sierra (possible also a problem with El Capitan) you need to update the firmware of the keyboard… The weird thing is the keyboard does work in Windows running in Parallels Desktop on macOS and subsequently stays working after Parallels is closed until you restart the pc or reconnect the keyboard… Seems to be some kind of power management issue.
Anyway… Ducky seems to hide this specific firmware update. It’s not listed on their website (http://www.duckychannel.com.tw/en/firmware_updater.html). I finally received the newest firmware after quite some delay from their support department.
You can find the new firmware here (only use with exact model DK 2108!):
It consists of an .exe (the firmware updater tool) and a .bin (the firmware you need to select in the tool). You need to run the update process on Windows.