DVDFab works with UHD-friendly BD XL drives, but not with official drives as of now, because they require new and specific authentication.
Supported UHD-friendly Drives:
LG WH16NS40 (NS50)
LG BH16NS40 (NS50)
BU30N (laptop) and clones from Asus (eg. BW-16D1HT fw 3.0)
Note: the firmware of certain drives has a bug — a UHD disc may become unreadable if the drive goes into standby mode. But there is a workaround: eject and reload the disc shall fix the problem.
UHD Official Drives (not supported yet):
LG WH16NS60, BU40N, BU50N and clones from Buffalo
Pioneer S11/211, XD06, XD07 and clones from Logitech
Note: Don't update any firmware on these drives as they will lose the capacity to read UHD discs!