BIBM and UEFI/GPT

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Re: BIBM and UEFI/GPT

Postby CyberSimian » Tue May 09, 2017 10:45 am

Bob Coleman wrote:
> If I make a full disk backup of the GPT disk, attempt to convert it to
> EMBR, and somehow end up with an unbootable mess, can I have reasonable
> confidence that restoring the full disk backup would restore the disk to
> its working GPT state?

I tried converting the Windows 10 pre-load on my Lenovo from UEFI/GPT to MBR/EMBR by following the instructions in the Terabyte Knowledge Base article 580, but there is a critical instruction missing, and the result was a system that was unbootable and apparently unrepairable. This was for Windows 10; I don't know whether this also applies to Windows 8/8.1 and/or Windows 7.

Fortunately, I found the missing information in a thread on this web site (my thanks to the person who posted it -- sorry, but I did not record your name). So my second attempt at converting UEFI/GPT to MBR/EMBR (after restoring the image that I had created previously) worked correctly. This is the missing instruction:

(15b) Check the folder "efi" in the root directory of the Windows Recovery Drive (usually a memory stick). If the folder is named "efi", rename it to "efi.old".

If you don't do this, Windows becomes confused and the system won't boot and cannot repair itself.

-- from CyberSimian in the UK
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Re: BIBM and UEFI/GPT

Postby Bob Coleman » Tue May 09, 2017 11:25 am

CyberSimian wrote:

> I tried converting the Windows 10 pre-load on my Lenovo from UEFI/GPT to MBR/EMBR by
> following the instructions in the Terabyte Knowledge Base article 580, but there is a
> critical instruction missing, and the result was a system that was unbootable and
> apparently unrepairable.
...
> If you don't do this, Windows becomes confused and the system won't boot and cannot
> repair itself.

So even though you got a system that was unbootable and unrepairable, you were able to restore a full disk backup of the GPT disk to get a bootable system again?
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Re: BIBM and UEFI/GPT

Postby tas3086 » Tue May 09, 2017 1:18 pm

CyberSimian wrote:

> The reason why I keep the NVMe SSD as GPT is related to updating the BIOS on the
> Lenovo.
> -- from CyberSimian in the UK

Interesting. My Lenovo handles the BIOS update only through the Windows Update Capability. There is no manual way to update/restore/backup the BIOS. I guess that I will have to do something similar as I bet the windows update will not work through a Legacy mode either. Thank you for the information, before I made a mistake!
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Re: BIBM and UEFI/GPT

Postby CyberSimian » Tue May 09, 2017 4:06 pm

Bob Coleman wrote:
> So even though you got a system that was unbootable and unrepairable, you were able
> to restore a full disk backup of the GPT disk to get a bootable system again?

It was over 6 months ago when I did this, and I am not sure that I can remember the exact details. At the time, I had only BING (not BIBM), and BING does not recognise GPT, so I initially imaged all of the partitions using a "System Rescue" live-linux CD. Looking at my notes I see that I used:

(1) "sfdisk" to image the partition table,
(2) "partimage" to image the partitions that had recognisable file systems,
(3) "dd" to image the partitions that did not have recognisable file systems (actually, only the "Microsoft Reserved" partition).

So I think that I restored these images using the "System Rescue" CD. Later I purchased BIBM, but I have not actually used BIBM in the scenario that you have posited. Still, if Terabyte Support say that it should work, then I guess that it should work!

-- from CyberSimian in the UK
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Re: BIBM and UEFI/GPT

Postby CyberSimian » Tue May 09, 2017 4:22 pm

tas3086 wrote:
> Interesting. My Lenovo handles the BIOS update only through the Windows Update
> Capability. There is no manual way to update/restore/backup the BIOS. I guess that
> I will have to do something similar as I bet the windows update will not work through
> a Legacy mode either. Thank you for the information, before I made a mistake!

My Lenovo uses the "Lenovo Companion" application to look for updates on the Lenovo web site, and download and install the updates that you select. The updates are such things as new driver versions, updates to the Lenovo applications, and updated BIOS. But it does not include Windows updates, which are downloaded and installed using the usual "Windows Update".

It is also possible to download these Lenovo updates manually, including new BIOS versions. After download, you run the EXE to create the directory on the "C:" drive, and then run the BIOS updater program to actually update the BIOS. All this is done whilst running Windows 10.

I would be surprised if Microsoft's "Windows Update" offered to update the BIOS (but maybe it does).

-- from CyberSimian in the UK
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Re: BIBM and UEFI/GPT

Postby TeraByte Support(PP) » Tue May 09, 2017 4:30 pm

Creating a backup image of the entire drive is recommended because there will be partitioning changes made. If you use the chgdtype.tbs script then it's a fairly automated procedure. If you run into issues you can restore the image and try again, if necessary.

Since you would normally be using boot media to do the conversion (TBWinRE, IFL, etc.) you may want to verify that it boots properly using Legacy mode before you begin as this is the mode that would be required after converting. In the case of boot media that supports both Legacy and UEFI you may need to select the Legacy (non-UEFI) version from the BIOS Boot Menu or alter the boot media to prevent UEFI mode from booting (as CyberSimian did by removing the "efi" folder).
Paul Purviance
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Re: BIBM and UEFI/GPT

Postby Bob Coleman » Fri May 12, 2017 4:26 pm

chgdtype.tbs appeared to work flawlessly to convert the disk to MBR, but I couldn't boot the result (no BIOS option that I could find to boot the hard disk in legacy mode).

The good news and the reason I'm posting again is to report for anyone who may be concerned about this that restoring the full disk backup made before converting put everything back the way it was before the conversion and the system is in good shape again.

I'm nearly resigned to the fact that I'll have to live with GPT and no multi-booting on this system.
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Re: BIBM and UEFI/GPT

Postby Brian K » Fri May 12, 2017 4:54 pm

Bob Coleman wrote:

> couldn't boot the result (no BIOS option that I could find to boot the hard
> disk in legacy mode).
>
Bob,

In you BIOS/firmware have a look at the Secure Boot setting. Does it have 2 options? UEFI and Other OS?
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Re: BIBM and UEFI/GPT

Postby Bob Coleman » Sat May 13, 2017 7:03 pm

Yes, two options, UEFI and Legacy. It had seemed to me that the Legacy option didn't actually boot the converted HDD, but I finally got it done. After what seemed to be multiple unsuccessful attempts with chgdtype.tbs, I was successful using the steps in http://www.terabyteunlimited.com/kb/article.php?id=580 . It's not actually clear to me at this point whether there was anything wrong with the chgdtype.tbs process or whether coincidentally, I finally got the right combinations in the BIOS at the same time I switched approaches.
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Re: BIBM and UEFI/GPT

Postby Brian K » Sat May 13, 2017 7:11 pm

Good news. If you have CSM (Compatibility Support Module) in the BIOS, it should be enabled when using Legacy mode.
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