I have a perfectly OK running installation of Knoppix 7.2 in a USB 3.0 External Hard drive. When I use that drive in a PC it boots OK, but when I try to boot in in the mac mini, a black screen appears saying "boot error".My mac mini does not have OS X installed but Linux Mint.How can I solve this, so I can use my Knoppix in both machines?Thanks in advanceNacho