setup arch-linux on odroid xu(3/4) C2 pine64

http://odroid.com/dokuwiki/doku.php?id=en:xu3_bootmode_configuration [Boot mode configuration] http://archlinuxarm.org/platforms/armv7/samsung/odroid-xu3 [archlinux ODROID-XU3 Home]

https://magazine.odroid.com/article/emmc-recovery-resetting-the-odroid-xu4-emmc-module-to-fix-boot-issues/

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TODO: - one step image creation

install/install.sh <hostname>

will create a bootable disk on /dev/mmcblk1