Sorry to “necro” this thread, but I just got around to enabling and testing out your UPS kill command suggestion. Everything shutdown as planned, including the UPS itself. Once I restored wall power to the UPS, power started flowing to the server automatically, the BIOS detected it, and the server booted-up on its own! Success! ESXi is back up and VMs are still in the process of auto-starting. This is exactly how I wanted it all to work.