I originally booted from CD and used the command line usbinstall to install to USB stick, which produced the following in extlinux.conf (I added noswap when prompted for additional boot codes):
DEFAULT tinycore
LABEL tinycore
KERNEL /boot/bzImage
APPEND initrd=/boot/tinycore.gz quiet noswap waitusb=5:UUID="b80d8c4b-1dc8-4bc6-8c45-7b47ba815e0e" tce=UUID="b80d8c4b-1dc8-4bc6-8c45-7b47ba815e0e"
It looks like for some reason the UUID parts weren't included in lafrana's config file code.