Comment 3 for bug 1459865

so issue seems to be that /root/dev does not exist. I created /root/dev and was mount /dev:

(initramfs) mount
rootfs on / type rootfs (rw,size=16445592k,nr_inodes=4111398)
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,relatime,size=16445608k,nr_inodes=4111402,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
copymods on /root/lib/modules type tmpfs (rw,relatime)
(initramfs) ls /root/dev
ls: /root/dev: No such file or directory
(initramfs) mkdir /root/dev
(initramfs) mount
rootfs on / type rootfs (rw,size=16445592k,nr_inodes=4111398)
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,relatime,size=16445608k,nr_inodes=4111402,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
copymods on /root/lib/modules type tmpfs (rw,relatime)
(initramfs) ls /root
lib dev
(initramfs) mount /dev /root/dev
(initramfs)