Used ubuntu virtual drive
Followed instructions at http://www.angstrom-distribution.org/building-angstrom to bitbake a kernel
Prepared SD card as described in http://code.google.com/p/beagleboard/wiki/LinuxBootDiskFormat
Followed instructions at http://elinux.org/BeagleBoardAndOpenEmbeddedGit#Create_partitions_and_format_the_SD-card for copying files to SD card
The boot partition wasn't enough so copied files from disk that came with it. This is because the new BB-xM doesn't have U-Boot in NAND Flash so needs it on the SD card.