ubuntu@ubuntu:~$ sudo gdisk /dev/sdd
GPT fdisk (gdisk) version 1.0.3

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.

Command (? for help): r

Recovery/transformation command (? for help): h

WARNING! Hybrid MBRs are flaky and dangerous! If you decide not to use one,
just hit the Enter key at the below prompt and your MBR partition table will
be untouched.

Type from one to three GPT partition numbers, separated by spaces, to be
added to the hybrid MBR, in sequence: 1 2 3 
Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): n

Creating entry for GPT partition #1 (MBR partition #1)
Enter an MBR hex code (default EF): ef02
Set the bootable flag? (Y/N): n

Creating entry for GPT partition #2 (MBR partition #2)
Enter an MBR hex code (default EF): ef00
Set the bootable flag? (Y/N): n

Creating entry for GPT partition #3 (MBR partition #3)
Enter an MBR hex code (default 07): 0700
Set the bootable flag? (Y/N): y

Recovery/transformation command (? for help): x

Expert command (? for help): h

Expert command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!

Do you want to proceed? (Y/N): y
OK; writing new GUID partition table (GPT) to /dev/sdd.
The operation has completed successfully.
ubuntu@ubuntu:~$