First, follow the instructions on this page up until it tells you to unmount root: http://archlinuxarm.org/platforms/armv7/samsung/samsung-chromebook-2
Dont unmount root yet. you need to run cp /lib/firmware/mrvl/* root/lib/firmware/mrvl
This copies the proper wireless drivers to your new installation (otherwise wireless will NOT work)
Now you can umount root and sync and reboot.
After rebooting, press Ctrl + u at the boot screen to boot to your SD card.