How to backup full-disk image ?

gkmbinh

Hi everyone.
I using only ubuntu-server on rk3288 Board.
I install alot of libs on the rk3288 board.
now I want o backup system to an image as backup.img
for : flash to new board with all libs aready installed.
or restore for error software board.
parameter file is default :

CMDLINE:console=tty0 console=ttyS2 earlyprintk root=/dev/block/mtd/by-name/linuxroot rw rootfstype=ext4 init=/sbin/init initrd=0x62000000,0x00800000 mtdparts=rk29xxnand:0x00008000@0x00002000(resource),0x00008000@0x0000A000(boot),0x00002000@0x00012000(misc),0x0001a000@0x00014000(backup),-@0x0002e000(linuxroot)