They use ACPI. Not using UEFI was a perfectly reasonable choice. The bootloader is fully open source, led to improvements in boot speed and security. Booting no

They use ACPI. Not using UEFI was a perfectly reasonable choice. The bootloader is fully open source, led to improvements in boot speed and security. Booting non-chromeos images is possible and reasonably well documented. A standard bootloader may seem nice from an interoperability standpoint, but I'm not sure UEFI is a great place to land.