GPT convertion

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DrTeeth
Posts: 1289
Joined: Fri Aug 12, 2011 6:58 pm

GPT convertion

Post by DrTeeth »

The GPT disk that I wish to convert to MBR has 7 partitions. I assume
I need to get that down to 4 for a successful convert?

Come are recovery partitions and driver partitions.

I have done a full backup and will keep what contents are useful
(drivers etc).

Assuming I do need to get rid of some partitions, which ones are
necessary for a GPT system to boot?

I did try a utility that I discovered, but it complained that I had
too many partitions for a convertion.
--
Cheers,

DrT

** Stress - the condition brought about by having to
** resist the temptation to beat the living daylights
** out of someone who richly deserves it.
CyberSimian
Posts: 130
Joined: Wed Aug 10, 2016 12:13 pm

Re: GPT convertion

Post by CyberSimian »

DrTeeth wrote:
> Assuming I do need to get rid of some partitions, which ones are
> necessary for a GPT system to boot?

As you have not told us what partitions your system has at the moment, it is a bit difficult for us to tell you which ones are required and which can be deleted.

My Lenovo laptop arrived with Windows 10 pre-installed and 7 partitions:

SYSTEM_DRV (260 MiB, FAT32, EFI System)
MS RESERVED (16 MiB, none, Microsoft reserved)
WINDOWS (908,058 MiB, NTFS, OS and preloaded apps)
LENOVO (25,600 MiB, NTFS, Preloaded apps and drivers)
WINRE_DRV (1,000 MiB, NTFS, Windows recovery)
LENOVO_PART (17,934 MiB, NTFS, Lenovo recovery)
LRS_ESP (1,000 MiB, FAT32, OEM)

"LENOVO_PART" and "LRS_ESP" are part of the Lenovo "One Key Recovery" system. Removing those means that One-Key-Recovery would no longer work.

"WINRE_DRV" is part of the Windows recovery system. You can remove that if you first use the REAGENTC.EXE to unlink the OS partition from the recovery partition:

reagentc /disable

"LENOVO" is a simple data partition that contains Lenovo drivers, and can be removed.

"WINDOWS", "MS RESERVED", and "SYSTEM_DRV" must remain if you want your system still to boot in UEFI mode.

Of course, these are the partitions that were on my system (I converted to MBR, so they no longer exist). It is difficult to know whether any of this is relevant to your system.

-- from CyberSimian in the UK
Brian K
Posts: 1978
Joined: Fri Aug 12, 2011 1:11 am
Location: NSW, Australia

Re: GPT convertion

Post by Brian K »

DrT,

You could convert to EMBR and then install BIBM to boot your OS. Unlimited Primaries.

When you convert from GPT to EMBR or MBR the MSR and ESP are deleted. So if you want to convert to MBR you could start the conversion with 6 primary partitions. I suggest moving the recovery environment to the Win10 partition and then deleting the recovery partition. Then you would have 6 primary partitions.
DrTeeth
Posts: 1289
Joined: Fri Aug 12, 2011 6:58 pm

Re: GPT convertion

Post by DrTeeth »

On Fri, 3 Aug 2018 18:33:05 EDT, just as I was about to take a herb,
Brian K disturbed my reverie and wrote:

>DrT,
>
>You could convert to EMBR and then install BIBM to boot your OS. Unlimited Primaries.
>
>When you convert from GPT to EMBR or MBR the MSR and ESP are deleted. So if you want to convert to MBR you could start the conversion with 6 primary partitions. I suggest moving the recovery environment to the Win10 partition and then deleting the recovery partition. Then you would have 6 primary partitions.
>

That is indeed the plan, to convert to EMBR and use BIBM. From further
reading since my OP, if there are more than 4 partitions, an EMBR
drive is automatically created (using TOSDTS Pro script).
--
Cheers,

DrT

"If you want to find out what is wrong
with democracy, spend five minutes with
the average voter". - Winston Churchill
DrTeeth
Posts: 1289
Joined: Fri Aug 12, 2011 6:58 pm

Re: GPT convertion

Post by DrTeeth »

On Fri, 3 Aug 2018 13:35:27 EDT, just as I was about to take a herb,
CyberSimian disturbed my reverie and wrote:

>As you have not told us what partitions your system has at the moment, it is a bit difficult for us to tell you which ones are required and which can be deleted.

Good point, well made.

I have the same partitions as you have. I am running Win 8.1 - x64.
--
Cheers,

DrT

"If you want to find out what is wrong
with democracy, spend five minutes with
the average voter". - Winston Churchill
DrTeeth
Posts: 1289
Joined: Fri Aug 12, 2011 6:58 pm

Re: GPT convertion

Post by DrTeeth »

On Sat, 4 Aug 2018 04:13:38 EDT, just as I was about to take a herb,
DrTeeth disturbed my reverie and wrote:

>That is indeed the plan, to convert to EMBR and use BIBM.

Hit a brick wall or two. TBOSDT will not accept my correct name and
BIBM serial number. These were entered during the makedisk process and
then had to be again on booting the flash drive.

As posted in the BIBM section, I could not use the ISO to make a GPT
flash drive in the same way I can with IfL. Would changing the BIOS to
legacy be okay before the convertion so I can boot the MBR BIBM drive?
--
Cheers,

DrT

"If you want to find out what is wrong
with democracy, spend five minutes with
the average voter". - Winston Churchill
CyberSimian
Posts: 130
Joined: Wed Aug 10, 2016 12:13 pm

Re: GPT convertion

Post by CyberSimian »

DrTeeth wrote:
> Would changing the BIOS to
> legacy be okay before the convertion so I can boot the MBR BIBM drive?

The BIOS in my Lenovo has two possible values for the "Boot Mode" setting: "UEFI", and "Legacy Support":

"UEFI" means that the system will boot ONLY in UEFI mode.
"Legacy Support" means that the system can boot in either UEFI mode or MBR mode.

If your system is similar, changing to "Legacy Support" will still allow you to boot in UEFI mode (until you have completed the conversion), but it should allow you to boot a USB memory stick in MBR mode.

-- from CyberSimian in the UK
DrTeeth
Posts: 1289
Joined: Fri Aug 12, 2011 6:58 pm

Re: GPT convertion

Post by DrTeeth »

On Sat, 4 Aug 2018 06:33:12 EDT, just as I was about to take a herb,
CyberSimian disturbed my reverie and wrote:

>The BIOS in my Lenovo has two possible values for the "Boot Mode" setting: "UEFI", and "Legacy Support":
>
>"UEFI" means that the system will boot ONLY in UEFI mode.
>"Legacy Support" means that the system can boot in either UEFI mode or MBR mode.
>
>If your system is similar, changing to "Legacy Support" will still allow you to boot in UEFI mode (until you have completed the conversion), but it should allow you to boot a USB memory stick in MBR mode.

I'll give that a go later. Thanks for the extra information. I am
completely out of my depth with respect to UEFI/Secure boot/GPT, so
your input is VERY welcome.
--
Cheers,

DrT

"If you want to find out what is wrong
with democracy, spend five minutes with
the average voter". - Winston Churchill
Brian K
Posts: 1978
Joined: Fri Aug 12, 2011 1:11 am
Location: NSW, Australia

Re: GPT convertion

Post by Brian K »

DrT,

First, get your UEFI/BIOS setup for MBR booting. In the Boot section...

Disable Secure Boot. Your new setting will probably be "Other OS"
Enable CSM (Compatibility Support Module). Called Legacy in some BIOS.

Plug in the IFL UFD. Access your Boot Menu. It's likely you will see two entries for the UFD. Choose the one that doesn't have UEFI in the line.

In IFL click the TBOSDT icon and enter...

runtbs chgdtype.tbs

You are on the way. Assuming you choose EMBR you will need to install BIBM to boot Windows.
TeraByte Support
Posts: 3076
Joined: Thu May 05, 2011 10:37 pm

Re: GPT convertion

Post by TeraByte Support »

you're using the latest version 1.81 ?
(ver command)


"DrTeeth" wrote in message news:15474@public.tbosdt...

On Sat, 4 Aug 2018 04:13:38 EDT, just as I was about to take a herb,
DrTeeth

disturbed my reverie and wrote:

Hit a brick wall or two. TBOSDT will not accept my correct name and
BIBM serial number. These were entered during the makedisk process and
then had to be again on booting the flash drive.

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