$ sudo dd if=/dev/zero bs=1M count=32 of=/dev/sda4
$ sudo dd if=/dev/zero bs=1M count=32 of=/dev/sda3
$ sudo dd if=/dev/zero bs=1M count=16 of=/dev/sda2
$ sudo dd if=/dev/zero bs=1M count=32 of=/dev/sda1
$ sudo dd if=/dev/zero bs=1M count=32 of=/dev/sda