15 DC15250, how to setup multiboot on new laptop

Question

I'm wanting to setup multiboot on a new Dell 15 DC15250 laptop computer which is running Windows 11. When I start the BIOS I have been able to figure out how to boot different devices but when it comes time to make changes to the BIOS settings it is all pretty confusing. I should point out that I've been using Windows since its' inception and have done this on every prior version of Windows that I've used.

The answer might be as simple as referring me to some documentation.

aajax · Accepted Answer

Just so you know the link to a User Guide provided in that post is not working.

However, the topic seems to refer to using the Windows installer to install a new version of Windows. I believe way back in the day I did use that method. However, ever since, at least Windows 7, I've been using a different method. It essentially involves using the DISM command to capture & apply images. Using DISM I can capture an exact duplicate of an operational Windows system. In that, all custom setup as well as installed application programs are included in the captured image. Even connections to cloud services appear to be the same for both instances of Windows. The only thing you need to do to the new Windows partition is use the registry editor to revise the drive letter on the new partition so it becomes the C: drive rather than the one where the image was applied.

I've already completed the setup, capture, and application of the system desired. The last step is getting the Windows Boot Manager to recognize the new image.

From review of past files involved in undertaking this process it looks, to me, like the answer is running the BCDedit command to update the Windows Boot Manager. For some reason I was thinking I did this using the GUI for the BIOS. It now looks like I need to spend some time reviewing the BCDedit command which is also pretty complicated.

With Christmas approaching it looks like I'll have to postpone that for a little while. However, at present, I'm thinking that is when I'll be able to update this topic with findings.

For now, thanks very much for your help and I hope a Merry Christmas is also part of your plan.

ejn63 · Answer

You do not need to make UEFI changes. To boot from another device, that device must have a UEFI compliant operating system on it, and you start it by pressing F12 a few times at powerup -- if the device is UEFI compliant, it will appear as bootable. Select it and the system will boot from it.

Note: systems no longer have the ability to boot from legacy devices -- the device must be UEFI compliant.

aajax · Answer

The device is the same SSD being used to boot Windows 11. Multiboot means (to me anyway) booting another partition which contains another instance of the same operating system. When booting using F12 as you describe, one of the Options is called "Windows Boot Manager" (WBM). I believe what I want to do is add another bootable partition to WBM. At least that is how it has always worked in other versions of Windows. Then when you boot the computer normally, no need for F12, WBM provides a list of available systems to boot. Those systems do not have to be located on the same device but in this case they will be.

(edited)

ejn63 · Answer

The answer depends on what other OS you plan to run -- if it's Windows, you can set up a multiboot with Windows 11 as you have with other versions (subject to the restrictions of secure boot and UEFI; you won't be able to multiboot a legacy version of Windows). There are virtualization options for running non-UEFI aware Windows on newer systems.

If it's Linux you want to boot, that's a different story and likely best done with a Linux boot loader (Grub, etc.).

aajax · Answer

Right now it is another instance of Windows 11 that I want to setup. When looking at the BIOS setup screen it is not clear how to do that.

Is there some documentation available that explains in some detail what all the settings are used for. This is something where I'd like to avoid engaging in a trial and error approach.

ejn63 · Answer

https://learn.microsoft.com/en-us/answers/questions/4299036/how-to-install-and-use-two-separate-windows-11-ins

aajax · Answer

Well now, looks like I was headed in the right direction. It turns out that the specific action I was stuck on can be fixed quite easily with the BCDboot command which is kind of a mate to BCDedit which was also needed to refine some of the settings once I got the Windows Boot Manager working.

Many thanks for help provided on this post.

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15 DC15250, how to setup multiboot on new laptop

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