Well I finally got my copy of The Martian, UHD version from best buy, and loaded into my LG BH16NS40 BDXL drive (September 22, 2015 Build running Rom Ver:1.00 bought from Amazon US), and just like previously mentioned (with a WH16NS40 of recent build) the LG BDXL Drive read the UHD disc without problems. This UHD disc is unreadable in my other Blu-ray drives (Pioneer BDR208B and LG GGC-H20L). I have a MacPro and the Mac reports a used disc capacity as 52.54 GB with a total capacity of 69.54 GB (MacOs calculates GB differently), consistent with others conjecturing that this is a 66 GB double density disc. And just like reported the olderfirmware updates listed on the LG website for this drive do not work, with a Checksum error when I try to update the firmware. I have also tried to see if AnyDVD HD can read decode this drive using a Windows XP virtual machine, and as expected it error out as an unrecognizable format. I also have just set up a Samsung UBD-K8500 UHD player. But I have not tried to burn any BDXL discs and see if the Samsung player can read them.