mbr2gpt

10 years later

ghost

ghost

— 2 min read

finally converting my mbr windows partition to gpt... many years in the waiting i guess? this has all been working on moving my windows disk to a gpt formatted disk after moving from a dual booted computer to one dedicated to gaming. this adventure has been a number of years in the making as this pc first started as a windows 7 pc and then eventually became what it is now.

attempts at conversion

i first tried to use mbr2gpt and made an attempt at fixing the partition. this kind of worked. after moving the partition around with gparted i tried to use mbr2gpt a couple times and it always complained about no free space. i tried 500mb and 700mb at the beginning and plenty of space at the end. each time i moved the partition in gparted to had to go through the dance of

mbr2gpt /convert - couldnt find space
bootrec /scanos - found an os
bootrec /rebuildbcd -found the os and it asked to add it to the boot rec. i could now boot to this partition at this point ok as well
mbr2gpt /validate - validated ok!
mbr2gpt /convert - couldnt find space....

so i started doing some research on what mbr2gpt actually does, and found a pretty good microsoft article that gave some ideas

https://learn.microsoft.com/en-us/windows/deployment/mbr-to-gpt

i was able to see that my partitions do not match what it appeared to be expecting in the examples. so with that detail i went with trying to change the partitions and volumes to something that aligned with the example.

DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     F   CENA_X64FRE  UDF    DVD-ROM     4027 MB  Healthy
  Volume 1     C   System Rese  NTFS   Partition    499 MB  Healthy
  Volume 2     D   Windows      NTFS   Partition     58 GB  Healthy
  Volume 3     E   Recovery     NTFS   Partition    612 MB  Healthy    Hidden

DISKPART> select volume 2

Volume 2 is the selected volume.

DISKPART> list partition

  Partition ###  Type              Size     Offset
  -------------  ----------------  -------  -------
  Partition 1    Primary            499 MB  1024 KB
* Partition 2    Primary             58 GB   500 MB
  Partition 3    Recovery           612 MB    59 GB

DISKPART> detail partition

Partition 2
Type  : 07
Hidden: No
Active: No
Offset in Bytes: 524288000

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
* Volume 2     D   Windows      NTFS   Partition     58 GB  Healthy

DISKPART> exit

but the data

so doing this setup i did have to nuke the partition i was trying to work with. that was fine though, i had a backup snapshot that i had been working from since all of this was in my nas and not doing this on the actual gaming box yet.

after the new partitions were written i used the dd commands that i mentioned in a previous article to image the actual data partition which contained the original c drive. but they were slightly different since they were remote dd commands over ssh. since i was going from a remove filesystem onto this one i had to tell it where to seek but it was a little different than the other article. the skip had to be on the input section.

ssh root@remoteserver dd if=/dev/zd288 skip=endOfPartitionYouDontWant | sudo dd of=/dev/nvme0n1p3 status=progress

Well this didnt work because i ran out of space on the drive, so now i have to resize the partition. but i didnt want to do that on the zvol on the nas so i dumped the partition to disk and resized with parted. more to come...

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