I did a full install opensuse 15.3 and mswin. It booted normally then two boots later. MSwindows grabs control with no boot loader with opensuse. It boots to windows! I do an update install to fix the boot loader, turning on secure boot. It boots fine for about 3 boots. Then boots to windows without any boot loader. If I can’t stop this, I will have to remove the mswin 512gb drive card.
From now on, I will have to use rapid tapping of F11 on every boot. To force boot to opensuse.
Need help… ??
This behavior probably has to do with your UEFI BIOS.
I sometimes set my system to boot Windows. When in Windows, I use SHIFT - restart (hold down the SHIFT key while clicking “Restart”). That gives me an option to “boot from a device”. When I click that, “opensuse-secureboot” shows up as an option. So my reboot is then to openSUSE.
I don’t know if that will work for you, but it might be worth trying.
Try to use rEFInd.
In BIOS specify drive with GRUB (openSUSE) as 1st.
Thanks, I checked the bios. The changes I made were reset when I updated the bios. Once I put the changes back, it booted fine to opensuse. If this problem shows up again, i’ll post on here.
Perform “Load defaults” after BIOS update. Then correct settings if needed.
Thanks. I’ll keep that in mind.
I’m leaving the dual boot mostly behind (if no fancy IO stuff needed in Windows) and take the “Win as VM” way. Much more productive parallel universe 
Yet another solution: I stopped decommissioning of the i3-4130 by investing into a new case (60€), power supply (40€) and SSD (40€). This machine now serves as a completely independent backup system with Tumbleweed and Windows installed. Thus I avoid booting the i7-6700K into Windows as well as dealing with virtual machines. On the i3-4130 dual booting is as easy as can be.
Not viable with Win11 on old hardware. But I stay with Win7 till the end, hopefully. Isolated from any kind of web access, of course…
I have an Intel i7 10th gen - 4 cores - laptop and 8gb of memory. Will that be enough for VM win10? I have a win7 install dvd as well. Linux is on the 1tb drive and mswin10 is on the 512gb that came with it.
Could I just copy the mswin drive into a vm machine?
Win11 requirements for secure boot and TPM 2.0 as well as processor restrictions are removed if running it as a Virtual Machine. I have it working under both VirtualBox and VMWare on base systems that would not run it directly. As for Win7, totally agree, I use it to host my openSUSE servers which again run as VMs.
Processor sounds good but would want to double the memory (I have 26GB of memory but I can end up running several VMs at once).
Depends a bit on which VM system you are using. VMWare have a simple utility to clone a windows drive to a VMDK and then you can convert it into whatever format you need for the VM technology you want to use.
You will however probably run into an issue with the Win10 licence though, it will detect a hardware change and deactivate …
I run VB on 8gig no problem but I only use it to compile Windows programs. I have it set to use about 3.5 gig You may want more if you are using Windows as some sort of server.
I have to correct it’s an i5 not an I7. It would be fun to get win7 as wm machine. Will I need to have internet access to use it?
Also, I need to fix an nvidia issue on ms10 machine. I’ll need to post on another forums. MSWIN is blocking my nvidia driver program settings. I can only change global settings. More reasons it’s a gaming only machine. 
i5 should be fine. You may need internet access to activate it but one issue would be sourcing Service Pack 1 as I don’t think it auto updates any more and you should install or the updates. There are other forums that are better suited to help you on these later points.
Thanks for the info.
I’ll post when I try win7 as a VM machine.