I *think* the boardids are listed somewhere on the rootfs, but I forgot a key part in the kernel config of my new box to investigate further...
EDIT: Meeh. Maybe not.
Code:
zgrep LOOP /proc/config.gz
# CONFIG_BLK_DEV_LOOP is not set
Ooops.
For a mostly-accurate chronological listing of board codenames, see
KindleTool.