Hello
Assuming that you just copied your root FS to another device you propably forgot to create the basic dev nodes on it. in /dev you need at least these files, to get it booting until udev is loaded
crw------- 1 root root 5, 1 22. Jul 12:12 /dev/console
crw-rw-rw- 1 root root 1, 3 7. Jun 13:32 /dev/null
crw-rw-rw- 1 root root 1, 5 7. Jun 13:32 /dev/zero
you can create these dev nodes on another linux box with
mknod /dev/console c 5 1
mknod /dev/null c 1 3
mknod /dev/zero c 1 5
da1l6