SOLVED Multibooting High Sierra and 2 Win 10 systems all on 3 seperate drives;

[Henties]

Your hardware problems might be related to firmware itself and settings, are all fast boot options and other Windows features turned off?

Hi @vulgo Yes for sure my boot options are as required by macOS as the bios.zip attachment will reveal.

Hence everything should be generated by the tool or automatically by Windows

That is indeed what I do and have always done. When generating the Windows boot code I always use the latest Windows PE environment which is currently at PE10, or at least that is what I have been using. In that environment boot code generation is totally automated. When you have 2 x Windows installations present in your machine it will generate the BCD store for dual booting Windows and place that BCD code in an EFI folder of one of the Windows incarnations, and not both. That type of dual booting Windows is far too cumbersome for me because Windows when booted requires to run under the C:\ drive designation with only one drive being able to be C:\ at any given time. The default entry in the Windows boot manager is usually C:\ therefore getting into Windows is straight forward. The problem manifests itself, for me at least, when one wants to get into the non default Windows installation from within the boot manager. By selecting the "other" Windows.
Windows drive letters get swapped and another "boot" process is invoked, which to me is rather ridiculous and time wasting. That is the reason, among other, why I finally decided to go for the single Windows boot option. That is accomplished automatically by only having one Windows present in the machine when generating the boot code. Once the first Windows is done remove the drive on which the first windows is installed and replace it with the 2nd drive containing Windows, generate the boot code for that and voila you are done. Now you can pick any one of the Windows drives to meander into via the bios boot selection Window, which in turn is invoked by pressing F12 when the machine is "starting". In this way one can have as many bootable operating systems to boot into that the particular bios of the machine can handle, macOS and Linux included. This is all simple and straightforward and working very well for me.
My Windows boot problems, manifesting themselves whenever I invoked the Windows boot process from the Clover boot menu, are something of the past. Windows now boots flawlessly every time even with the IGPU enabled in bios. I also experienced problems in the macOS environment, and still do whenever I restart the machine from within one of the Windows incarnations and then "meander" straight into the Clover boot menu and from there into macOS. The problems are that more often than not my sound will not work properly, my NIC will not have initiated properly, shutting the machine down causes it to rather reboot and lastly sleep becomes erratic. These are all well known problems for which a lot of people are still endlessly searching for solutions.
I prevent these nagging problems completely from occurring when moving from Windows to macOS by shutting the machine down switching power to the machine off and then holding down the power button for a few seconds to ensure that whatever remnants of Windows code remained in memory is wiped completely. When I now start macOS into this clean boot environment I have not yet noticed any hickups when working within macOS High Sierra.
All of the foregoing is reproducible and indicates to me that the 2 operating systems are mutually interfering with each other via the common shared memory pool. For instance when Windows is booted from the Clover menu it merges it's code that it wishes to place into memory with that which Clover has already placed there and visa versa.
Now I believe this all started when Clover enabled us to move away from EmuvariableUefi-64 and using instead AptioMemoryFix or one of the OsxAptioFix?drv-64 incarnations. I will experiment around that issue further down the line but am quite happy the way my machines are performing presently.
@vulgo I now suggest that you have a look at the "fire spitter image" and see whether you will be able to discover yourselves It should enable you to relax after this rather long winded dissertation of mine. Enjoy or destroy
Greetings

 

[Henties]

I have finally managed to get both of my hacks to triple boot with 2 Windows installations in the way I always wanted to with Clover.. After I managed to fix reboot issues as documented here https://www.tonymacx86.com/threads/...to-a-reboot-loop-from-the-clover-menu.254562/ I moved back to this thread to wind up and improve my triple booting setup used to date.
Each Windows drive now uses its own dedicated BCD code, of which each one resides in the EFI partition and folder belonging to the respective HDD, on which Windows resides which needs to be booted. Note this "pairing" is NOT strictly required as the BCD code is merely a pointer to the Winndows HDD on which the final boot code can be found. In other words the BCD code could also reside on another drive whether in an EFI partition or not.
Finally I incorporated the 2 Windows installations into the Clover GUI section as per the attached screenshots, and that finalizes the tripple boot
challenge in the most elegant way known to me. Years ago I also used this method with Chimera as a bootloader but forgot all about it when I finally moved to Clover, during which stage I had no need for dual or triple booting. As time flies past one tends to become rather more forgetful or is alzheimer perhaps getting a foothold
The attached screenshots speak a thousand words and should provide an interested hacker enough insight to enable him/her to venture into this
on own steam.
A special thanks to @vulgo who with his input and guidance helped me keep my feet on the ground which resulted in me cutting down my "dreaming" to realistic and achievable levels Thank you @vulgo including your patience that finally got this all working. Incidentally I have also
fixed the IGPU issue I had with Windows on my Haswell hack using a GTX 970. Anybody interested how I overcame that issue and retain hardware encoding as well as decoding functionality in macOS, just shout.

Greetings