Ubuntu details its UEFI secure boot plans

This functionality is required to get the little sticker, and ACPI functionality is tested by Microsoft. The problem with ACPI is that it's only tested under Windows, and our implementation isn't identical to Windows. That's not a concern at this level of firmware. Plus, like I said, this is functionality that's already present in the firmware that OEMs get. They'd need to actively put work into removing it.