Win 10 dual boot on a GPT disk

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Brian K
Posts: 2214
Joined: Fri Aug 12, 2011 1:11 am
Location: NSW, Australia

Re: Win 10 dual boot on a GPT disk

Post by Brian K »

Everything is working fine. The Windows OS on GPT drives are hidden in MBR Disk Management by default. All data partitions on GPT drives are seen.
With CSM enabled I don't have a Secure Boot setting in the BIOS. No big deal.

Thanks again. Very clever.
jbraner
Posts: 37
Joined: Thu Sep 01, 2011 6:05 pm

Re: Win 10 dual boot on a GPT disk

Post by jbraner »

This thread has been very helpful.
(I didn't really know very much about how UEFI/GPT etc worked until last week ;) )
I'll report back.
I'm going to install BIU tomorrow - but I won't try configuring the Windows parts on the GPT disk right away. I have a few other things to do first.
(like reorganising a few smaller data SSDs on to one big one)
jbraner
Posts: 37
Joined: Thu Sep 01, 2011 6:05 pm

Re: Win 10 dual boot on a GPT disk

Post by jbraner »

TeraByte Support(PP) wrote:
> jbraner wrote:
> > So, just to reiterate - I can "boot" my NVMe (GPT) disk with just
> > the BIU installed?
>
> Correct. If it was the only UEFI system installed then that's all the BIOS would find
> when searching.
>
> > If it all goes pear shaped - I can change my BIOS, boot the MBR disk -
> > which will load my current BIBM menu - and boot my current partitions?
>
> Correct. But be aware that for any drive/partition changes that may affect your MBR
> boot items you should check if anything needs adjusted. This is pretty much the same
> as when you add a drive or make partitioning changes with MBR-only.
>
> > with BIU - can I still see a MBR "data" disk? Or do I have to
> > change everything to GPT? (which I will do eventually anyway)
>
> You have control over both GPT and MBR/EMBR drives in BIU. You would configure the
> MBR "data" drive/partition the same as normal for each boot item.

Thanks for verifying! I now have a plan! ;)
jbraner
Posts: 37
Joined: Thu Sep 01, 2011 6:05 pm

Re: Win 10 dual boot on a GPT disk

Post by jbraner »

UPDATE 1:

I've installed BIU on to my NVMe drive.
NOTE: I don't find it straightforward how you tell it where to install. At first it installed to the wrong (a data) GPT disk. I just:
- uninstalled BIU
- disconnected all GPT disks and my current MBR Windows disk (to be sooper dooper safe)
- then reinstalled BIU - so now it's on the NVMe disk

There is nothing else on the NVMe disk - so it's just a blank BIU menu (as expected)

So now, with a little jiggery pokery in BIOS (I just saved two profiles to switch between - so it's easy) I can boot the BIU (blank) menu or my current working BIBM menu from the (E)MBR disk.
This is great. Now all I need to do is
- copy the Windows partitions over to th eNVMe disk (easy)
- and get them to boot (hopefully with the CHGDTYPE.TBS script, or the FIXBOOT one if that doesn't work)
- I can be free to mess around until it works - because my current partitions are intact - and I can always fall back to using them.


One thing I noticed:
For booting from CDROM, I use the BIBM menu with the "next BIOS device" ticked. This doesn't seem to be available in BIU - but the "direct boot" button lets me pick the CD/DVD drive (both "normal" and UEFI versions work) - so that will be OK.

I'm not going to work on the next part just yet - I've got a few other things to catch up on - but I'll report back when I do.
I *think* I will be setting up two separate EFI directories/entries for the two Windows partitions - and I'll try to label them so it's easy to tell the difference between them.

TBC... ;)
jbraner
Posts: 37
Joined: Thu Sep 01, 2011 6:05 pm

Re: Win 10 dual boot on a GPT disk

Post by jbraner »

UPDATE 2

SUCCESS!
I copied the Windows partitons over to the NVMe disk (with Acronis Disk Director)
Then I ran the fixboot script
(support had told me to use chgdtype - but the disk was already GPT. Maybe if I formatted the NVMe as MBR and copied the partitions across - this would have worked)
This script did the trick! It was easy to use, and figure out what I was doing.
It made two separate subdirs in the EFI partition.
All I had to do was create the menu entries in BIU, and after scratching my head a little - I was able to point them each to the correct path.
(I knew it was microsoft.001 and microsoft.002 - but I wasn't exactly sure where to find them. I found them though at
\EFI\microsoft.001\boot\bootmgfw.efi (and microsoft.002)
Then I found where to hide the "other" partition for each one (slightly different than BIBM) - and we're in business!

Thanks a lot Brian and "support" for hellping point me in the right direction. You have to have an idea what you're trying to do and how this stuff fits together - to have half a chance ;)

PS - I'll just make sure everything looks good, and then I can retire the MBR disk (hidden from the GPT booting partitions) and go strictly UEFI.
Also I'll read up a little to try to get my terminology right... ;)
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