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I have a very peculiar condition where I need GPT based disk for hackintosh. I also want to install the following distros:

* Ubuntu 16.04
* Elementary OS Luna (Ubuntu 12 based)

I'm pretty confused by now as to whether I can install the above using legacy boot on GPT partition. Is this possible?

user3677331
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1 Answers1

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Yes. Legacy can be installed on a GPT Partition Table disk format. By the way, it's the new standard that's gradually replacing MBR. This format type is a better choice because it doesn't have the MBR limits.

Read and booting to GPT Partition table drives are compatible with all Intel-based computers since 2003. It's quiet unlikely that you will find a PC that can't read the format.

Results of Copy from MBR to GPT:

I used dd to copy a partition from source drive in MBR and destination drive in GPT partition. The only partition that was affected was the destination partition on the destination drive. All the other partitions on the destination drive remained in tact.

The destination drive was a bootable drive with a GPT partition table. The OS on the 120G drive is Ubuntu 16.04. The drive boots in either a computer that has EFI compatible or just legacy. I tested booting the drive to a 10 year old Dell laptop, that only has legacy support. It booted flawlessly before the copy and after the copy to the Laptop, as my computer that has the UEFI capability.

DD Copy Script

When I perform what I consider critical task such as this, I usually create a very easy to follow script first and study it closely and run the critical command from the script. Also I have a huge command history buffer, and try to minimize accidentally running a wrong commandline from the history. I call the script from the directory with: ./ddcopy.sh

The script I used is:
ddcopy.sh:

#!/bin/bash

source="/dev/sdb1"
destination="/dev/sdc4"

read -p "Copy from device $source to $destination: [y/n] " -n 1 -r
if [[ $REPLY =~ ^[Yy]$ ]]
then
    # do dangerous stuff
    echo "..."
    echo "Proceeding..."
    time sudo dd if="$source" of="$destination" bs=4M status=progress ; espeak "Application Completed."
else
    echo "..."
    echo "Applicaton canceled."
fi

After the copy I used gparted edit's check command to correct the integrity of the partition. The two partition sizes were different. While the disk mounted and the data's checksum was correct, the check corrected the size discrepancy.

Integrity of the Files verification

I ran a checksum check of the files on the source and and the destination partitions to ensure the integrity of the files transferred. I also performed before and after checksum test of the destination drive to ensure the other partitions remained unaffected after the dd copy.

An example of the multiple checksum test is:

$ sudo mount /dev/sdb1 /mnt
$ md5sum /mnt/* >> ~/checklist2.chk ; espeak "Application completed"
L. D. James
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