Generates and writes a new UUID for an NTFS partition. Used for disks from the same manufacturer that have the same UUID. This allows you to mount via UUID in /etc/fstab.

rewrite_ntfs_uuid.py

#!/usr/bin/env python3
# file: rewrite_ntfs_uuid.py

import sys
import random
import os

# partition file
fileName = sys.argv[1]  # e.g. /dev/sdb1
UUID_OFFSET = 72  # location of NTFS UUID
UUID_LENGTH = 8


def print_hex(*args, **kwargs):
    if len(args) == 1:
        data = args[0]
        fmt = None
    if len(args) > 1:
        fmt = args[0]
        data = args[1]
        args = args[2:]
    else:
        raise ArgumentError('must have a byte array')
    hex_str = ''.join('{:02x} '.format(x) for x in data)
    if fmt:
        print(fmt.format(hex_str, *args, **kwargs))
    else:
        print(hex_str)


def read_uuid(fh):
    fh.seek(UUID_OFFSET)
    data = fh.read(UUID_LENGTH)
    return data


def write_uuid(fh, uuid):
    fh.seek(UUID_OFFSET)
    fh.write(uuid)
    fh.flush()
    os.fsync(fh.fileno())


def _main():
    new_uuid = bytes(random.randint(0, 255) for _ in range(UUID_LENGTH))

    print_hex('generated uuid: {}', new_uuid)

    with open(fileName, "r+b") as fh:
        data = read_uuid(fh)
        print_hex('current uuid: {}', data)
        write_uuid(fh, new_uuid)
        data = read_uuid(fh)
        print_hex('new uuid: {}', data)


if __name__ == "__main__":
    _main()