Windows 10: Can anyone help me get Windows 10 bootable again after formatting my EFI partition?

Hello guys, I'm going to try and explain this in as much detail as possible in hopes that one of you kind souls out there will be able to help me out.

|-----Here is my hardware information:

I have a Dell Venue 11 Pro 7140 tablet and it's running W10 Enterprise 2004 (Slow Ring). It only has one drive, an SSD (Micron M600).

My Boot Sequence in my BIOS is listed as:

# Name
1 Android-x86 9.0-r2
2 Windows Boot Manager
3 UEFI: Micron_M600_[bunch of letters and numbers]

My Boot List Option is set to UEFI (not Legacy) and Secure Boot is OFF. Not sure if this helps or not, but if I click the View button in the Boot List Option area it pops up a window and lists Windows Boot Manager with a filename of:

\EFI\Microsoft\Boot\bootmgfw.efi

and Android-x86 9.0-r2 with a filename of:

\efi\Android\BOOTx64.EFI

Both give a File System List of:

HD(2,GPT,[lots of letters and numbers])

Under Advanced Boot Options, Enable Legacy Option ROMs is checked.

I think I should also mention that various partition manager programs listed my SSD as GPT.

|-----Some backstory and the problem:

I've experimented with running other OSs in the past, but always from a live CD(/live USB) because setting up multiboot has always seemed a bit complicated to me, and easy to mess up in a way that will cause a huge headache (as it did). But I was feeling adventurous last night and after having run Android x86 off of a live USB in the past, I wanted to try permanently installing it on my HD and setting up multi-boot with Windows.

I used a partition manager program to shrink my main Windows install partition down by 16GB and left the space unallocated. Then I created a bootable USB stick with the Android x86 ISO and Rufus. I booted into it under Legacy mode rather than UEFI mode (which I later realized was my mistake) and I used the "cgdisk" utility that comes on the Ax86 installer to format the 16GB of unallocated space to ext4 and then wrote the partition to the disk.

Unfortunately here's where I ran into an error that wasn't covered in the Ax86 installation guide... After I chose to install Ax86 on the new partition I just created, the installer asked me if I wanted to install GRUB, to which I answered Yes, but then a warning box popped up saying:

Warning Found GPT on /dev/sda. The legacy GRUB can't be installed to GPT. Do you want to convert it to MBR? WARNING: This is a dangerous operation. Etc...

I clicked No, because I didn't think I wanted to do that, and my machine rebooted. So after searching for quite awhile on Google and the Ax86 Google Groups, I couldn't seem to find any relevant advice about what to do in this situation and only got more confused. Eventually, I found somebody who had replied to a post in the Google Group with instructions that seemed relevant to my situation and hardware setup. He suggested to point the Ax86 installer to my 100MB EFI "fat32" partition first, instead of the 16GB ext4 partition I had created, let it install GRUB2, and as soon as GRUB2 finished installing, reboot the machine. Then, after booting into the USB stick again, point the installer to the 16GB ext4 partition and let it run through fully, saying No when it asks if you want to install GRUB.

So I tried following these instructions (without realizing I needed to boot the USB stick using UEFI rather than Legacy) and pointed the installer to my EFI partition, it asked me if I wanted to format the partition, I clicked [Yes -] fat32, and then I got the same error message as before about GRUB not being able to be installed to GPT. I clicked No, and my machine rebooted, and then found myself in the unpleasant situation of not being able to get back into my Windows install (in hindsight, what else should I have expected after I just formatted my EFI partition? ).

This morning I finally realized that the mistake I made was not booting the Ax86 USB disk in UEFI mode, which would have used GRUB2 rather than the original GRUB. So after realizing this, I was able to install GRUB2 and Ax86 just fine, and now when my machine boots up it takes me to a bootloader screen where I can choose to launch either Ax86 or the option "Windows at hd0,gpt2". The problem is that I still can't boot into Windows. When I select Windows from the bootloader, I get a green screen (GSOD?) with the error:

Your Windows Insider Build ran into a problem and needs to restart. BAD_SYSTEM_CONFIG_INFO

and then after it reboots:

Your PC couldn't start properly and needs to be repaired. Error code: 0xc0000001

|-----What I have tried to do to fix it:

So I have a desktop PC that is running the exact same Enterprise 2004 (Slow Ring) build as my tablet, and I have used the "Create a recovery drive" tool built into Windows on that PC to create a recovery USB stick. I boot the recovery stick in UEFI mode on my tablet, but Automatic Startup Repair can't fix the problem. Using command prompt to check the the log file it generates ("D:\Windows\System32\logfiles\srt\srttrail.txt"), the only seeming anomaly is:

Test Performed: Name: Check for installed LCU Result: Completed successfully. Error code = 0x3f1 Time taken = 3406 ms

When I run DISKPART > list vol in the command prompt, here is the result:

Volume # Ltr Label Fs Type Size Status Info
Volume 0 C Recovery NTFS Partition 529 MB Healthy
Volume 1 D NTFS Partition 221 GB Healthy
Volume 2 FAT32 Partition 100 MB Healthy Hidden
Volume 3 E RECOVERY FAT32 Removable 7633 MB Healthy

And I don't know if this is helpful or not, but my default path when opening up command prompt is "X:\Windows\System32\".

Does anybody have any idea what commands I can run that will possibly get Windows booting properly again?

Thanks in advance for taking the time to read this and any help you may be able to offer me. I appreciate it!

submitted by /u/richbordoni
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