The BDR-209EBK is an awesome drive and absolutely makeMKV safe, incl FW1.54. You can downgrade from v1.54 to previous versions (did it myself) and also crossflash to the BDR-211 v1.53 to read UHD discs (again, done by myself). One important thing, don't crossflash to v1.54 of the BDR-211, you lose ...