If you would rather not replace your current version of Windows with Windows 10, you can set up a dual boot configuration. Then you should be able to boot from HD2 in bios.Dual boot is a configuration where you can have two or more operating systems installed on your computer. # create windows boot loader on the EFI partition, pointed to win10 Shrink desired=500 (shrink the partition by 500MB) # if you don't have free space on the drive, then shrink a partition Y by 500 MB The basic steps are like so, while booted into HD2: # look at the existing disk config Take a look at the steps and linked answers here, or a walkthrough with pictures here. Like Changan mentions, you need a new boot partition on HD2 first. This is not very obvious or well-documented, and it can be very difficult to fix if done incorrectly. Read through the answers here to get an understanding of the process and tools (even though it's technically the opposite of what you're trying): How to use BCDEdit to dual boot Windows installations?. This is all most people want, and you can stop here unless you specifically need to boot from the bios menu Now booting your PC should skip the windows boot manager until you change the default again. Select which OS you want to use on next boot, and click Set as default.Open System Configuration ( msconfig) on your PC, and go to the Boot tab.Is this something I can achieve? Anyone friendly enough to share some links/guide for me to follow to execute this? My skill level with Windows is mediocre. I followed a guide online to get my current setup - but have lost the bookmark.don’t want to reformat either drive and loose data.going forward just use BIOS boot order to choose HD 1 or HD2 in the boot order for when I want my Win 10 or Win 11 install.have both HD 1 and HD 2 show up in the BIOS boot order screen (currently only HD 1 does).

In my BIOS boot order setup screen, there is only one entry for “EFI” - Windows Boot Manager (HD 1) … HD 2 doesn’t show up.

Current boot order is done via windows boot manager: I get a Windows Boot Loader prompt at startup to select the OS I want to boot into.

Win 11 installed on HD 1, Win 10 installed on HD 2

Dual Boot Windows Environment on separate HDs (one HD has Win 10 installed, the other HD has Win 11 installed).

Best dual boot manager