Win 10 dual boot on a GPT disk

[Brian K]

John, I'm not sure what you have done so far but can you try this....

BIBM is already installed. Delete all partitions from the NVMe SSD and make sure it is a MBR disk. Create a 50000 MiB NTFS partition on the NVMe SSD and install Win10 according to page 74 in the BIBM User Guide. This tells you to create the Boot Item, attempt to boot the Boot Item, which will fail of course and then install the OS to the 50000 MiB partition.

Any luck?

[jbraner]

Thanks Brian,

I've emailed support too - so they've also given me an idea.
I'm not sure yet - but they're implying that my current disk (MBR formatted SSD with the two Windows partitions) might still boot - even with BIU installed.
If that's the case - that would be great, as I can experiment and will eventually get the NVMe working as a GPT drive - practice and set it up - and then just copy over the current Windows partitions (and retire the current drive). Until then I can't really turn off CSM, or I won't see the current boot disk or my other MBR formatted data drive.

So, I'll have a think about it for a few days. There's no hurry as the current setup isn't broken. I was just going to change to GPT since I'm already in a little upheaval with my hardware upgrade

[TeraByte Support(PP)]

I have a system with BIU installed to an NVMe drive and BIBM installed on a normal drive. BIU boots the GPT Windows installations and BIBM boots the older MBR installs. With this type of setup you have to use the BIOS boot menu to switch between them (my system defaults to BIU). A little more complicated to deal with than a single install, but might be something to consider if multi-booting both types.

[jbraner]

That is exactly what I want to do!!
The "BIBM/boot the older installs" would only be temporary - until the GPT boots were set up properly - but at least I'd have a failback

I've been having this conversation via email with support too (same person?) - so this sounds good.

So, just to reiterate - I can "boot" my NVMe (GPT) disk with just the BIU installed? This will give me the tools to set up the GPT boots.
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?

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)

Thanks a lot for the advice/information!!

[Brian K]

Paul, I'd forgotten you have been using BIBM and BIU in the same computer. For quite some time. How do you manage your UEFI BIOS settings with this setup?

John, please keep the progress reports coming. Very interesting.

[TeraByte Support(PP)]

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.

[TeraByte Support(PP)]

Brian K wrote:
> Paul, I'd forgotten you have been using BIBM and BIU in the same computer.
> For quite some time. How do you manage your UEFI BIOS settings with this
> setup?

CSM is enabled and configured to boot both UEFI and Legacy. BIU is set as the default boot item. When I want to boot BIBM I use the BIOS Boot Menu (F8 when booting) and select the drive with BIBM. When updating BIBM I use the manual method (selecting the partition, treat it as disk 0, etc.).

[Brian K]

Thanks. I assume Secure Boot is disabled all the time.

In general, are you a fan of Secure Boot in a computer? I wonder whether it's protecting me from something that is very unlikely to happen.

[TeraByte Support(PP)]

Brian K wrote:
> Thanks. I assume Secure Boot is disabled all the time.

It's shows enabled in the BIOS, but it's the "Other OS" type. Windows sees it as disabled. Depending on the BIOS there may be other options available.

> In general, are you a fan of Secure Boot in a computer? I wonder whether
> it's protecting me from something that is very unlikely to happen.

I generally have it enabled when it's not in the way of anything.

[Brian K]

Great instructions Paul. I'm just in the process of installing Win10 to a MBR disk. My BIOS setting were a little different from yours. I had to disable Secure Boot otherwise CSM kept reverting to disabled. But I'll look at this again after the install has completed.