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What is Significance of MSR, SYS, EFI partitions for Win 8.1 Native Bo


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What is Significance of MSR, SYS, EFI partitions for Win 8.1 Native Boot VHD? How?

I ask because I've built and native booted several variations of Win 8.1 VHDs on target SPro 3. I'd like to know pros & cons.

So, with a lot of help and input from multiple amazing people from multiple forums and coming closer to the goal of my project. I have found and tested the ways and means to complete the steps in my project. 
Some interesting questions and thoughts have come up. 


A - Was able to find articles that help bypassing Sysprep errors on Win 8.1
Did some extensive Driver Cleaning/ Reseting from OEM/Intel/Non MS drivers to MS Win 8.1 native drivers

e.g. Prototype sample runs involved Sysprepping Fresh Win 8.1 installs while eliminating issue causing Metro App packages. 

B - Played with DISM, Disk2VHD, GPTGEN in various configurations with Win 8.1

e.g. Prototype sample runs involved imaging Fresh Win 8.1 MBR/ BIOS installs and converting or applying them to GPT/UEFI VHDs and native booting them in Step C

C - Have been able to Native boot Win 8.1 VHDs using BCDBOOT: 

QUESTIONS & DECISIONS about MSR, SYS, EFI Partitions on Win 8.1 Native Boot VHD: 

I am left with some final decisions to make and questions.. 

Before I apply my Customized_Windows.WIM...
What kind of Partitioning structure should I CREATE IN/ FOR my FINAL VHD? 

I ask because I've built and native booted several variations of Win 8.1 VHDs on target SPro 3. 
Some with Single Partition Volumes and others with Sys+EFI etc. 

OPTIONS/ EXAMPLES of Sample VHDs executed & installed on Surface Pro 3:

DISM Installed Natively 

Vanilla Install via Hyper V
Possibly also doable using VDisk commands via Native Install as well. I guess. 
Also, during this Vanilla install it was trying to create the MSR partition in addition to the above. 

I did read about the MSR, SYS, EFI partitions online as well as how OSes can also run without those. 

Also, if ever V2P for Upgrading to Win10 and then P2V again smile.gif There were some workarounds posted on Technet (need to find link, will find and post) as Windows cant upgrade on Native Boot VHD. 

With single partition volume VHDs, its simple & clear how to APPLY and USE ..BCDBOOT. 
With these SPECIAL PARTITIONS, I am curious what would the best way to "direct" BCDBOOT > > > ?? From where to where? 



SPro 3 HDD (UEFI Only):

X61T HDD (BIOS Only):

Edited by crashnburn4u
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Since, we are trying to keep things Synced between Forums for the benefit of Members who may be only on One of the Forums. 




Referring to these 2 posts on the thread I created, please do share what would be suitable partitioning scheme for the .VHD? 

Should it be: 
Single Partition: [\WindowsOS]
2 Partition: [EFI Sys][\WindowsOS]


Do have a look at those replies and share your thoughts. If needed I can post/ requote some info (little confusing/conflicting) from there here below. 

In UEFI install the system (boot) partitionmust always be separate from the Windows partition.


Another example: Win 10 update works with a single partition.

Keep it simple: use one partition inside the VHD.


I wanted to create a Universal VHD that would also boot in all 3 environments listed below: (and move exclusively to VHDs) (http://www.andrewconnell.com/blog/Moving-Exclusively-to-Boot-to-VHDs)

- Native Boot (with Host OS)
- VM Boot (in Hyper V or VMWare) 

- Native Boot without a Host OS

e.g. Like the examples here 

Can I do this with the Single partition? If you say thats a fact, I will try another experiment and try out some more BCDBoot experiments smile.png

Edited by crashnburn4u
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