GPT fdisk (aka gdisk) by Roderick W. Smith, rodsmith@rodsbooks.com

This software is intended as a (somewhat) fdisk-workalike program for
GPT-partitioned disks. Specific advantages of gdisk, cgdisk and
sgdisk include:

 * Edit GUID partition table (GPT) definitions in Linux, FreeBSD, MacOS X,
   or Windows
 * Convert MBR to GPT or back without data loss
 * Convert BSD disklabels to GPT without data loss
 * Create hybrid MBR, which permits GPT-unaware
   OSes to access up to three GPT partitions on the disk
 * Repair damaged GPT data structures
 * The ability to specify sector-exact partition sizes
 * Clear identification of the number of unallocated sectors on a disk

WWW: http://www.rodsbooks.com/gdisk/
     http://www.rodsbooks.com/fixparts/