2 stupid questions: 1. the RK1 OS images say "preinstalled". Do the RK1s come with an image OS preinstalled? I don't believe this is the case 2. The RK1 OS images are

.img.xz

which means the BMC UI doesn't view it as an appropriate image to upload. Should the image be renamed to .img, or is there a better way to load this image?