https://bugs.freedesktop.org/show_bug.cgi?id=63935
--- Comment #8 from Benjamin Lee ben@b1c1l1.com --- I booted in Apple's BIOS emulation mode and found that UVD initializes successfully, so the problem is limited to EFI booting (like the former video BIOS issue).
Is there any debugging output I can provide that would help identify what is different when EFI booting?