Remove GPT from a disk under ubuntu

Suppose /dev/sdb is the device to be cleand

 

sudo apt-get install gdisk

sudo gdisk /dev/sdb

> Enter 2,  select GPT

> Enter  ?,  get command list

> Enter x,   expert mode

> Enter ?,  get command list

> Enter z,   destroy GPT

 

# create dos partition table, and partition

sudo fdisk /dev/sdb

# format the dos partition,   say /dev/sdb1

sudo mkfs.msdos /dev/sdb1