Reconstruct the EFI partition without data loss

[kikami]

[Guide] How to Reconstruct the EFI partition without data loss

Notes: After hours spent in forums, providing solutions that were not solutions, such as backing up and wiping... I decided to venture into the Windows side of creating an EFI partition. I found one guide detailing how to put back together the EFI using diskpart and the rest was pieced together by me.​

My issues: My EFI became corrupted, then converted to fat16. I eventually had to delete it. Reconstructing the EFI was the only way for me to get things going.. And since I'm dual booting, the EFI had the boot information of both. Now, make no mistake. My Bootloader was backed up but I couldn't find a way to construct the EFI. Hopefully this helps someone.

The guide I followed:
http://www.eightforums.com/general-support/52515-windows-8-cant-start-due-missing-efi-partition.html


Requirements:---
--There can not be unallocated free space other than the one that will be used to create the partition. (200mb minimum)
--It must be the 1 in the boot order.
--It must be labeled as EFI
--Windows is needed (Install disk/USB )
--Working UNIBEAST USB is needed to do some emergency booting.


(Given the fact that my EFI was borked, I was unable to reboot into Windows as well.)


*Insert Windows Recovery Disk
*Advanced Recovery tools
*CMD
Commands to be written in the following order:
Diskpart
List disk
Select disk 0 (May be different for others)
Create partition efi
List partition (to verify that it was created and if it is on the very top)
format quick fs=fat32 label="EFI"


A hidden system partition will be created labeled 'EFI'
*Using your UNIBEAST USB, enter your OS X partition.
*Remove USB


Verify that is working---
Clover Configurator > Mount EFI
(The partition should be mounted with no errors.)


Re-Install Boot Loader on to the hard drive with the post-install tools.


If restoring: Drag your EFI folder into the EFI partition and replace its contents after installing post-install tools.


Reboot---
EFI should be working properly now.

**Feel free to move this to the appropriate section if this is the wrong place.

 

[mactomaniac]

[Guide] How to Reconstruct the EFI partition without data loss

Notes: After hours spent in forums, providing solutions that were not solutions, such as backing up and wiping... I decided to venture into the Windows side of creating an EFI partition. I found one guide detailing how to put back together the EFI using diskpart and the rest was pieced together by me.​

My issues: My EFI became corrupted, then converted to fat16. I eventually had to delete it. Reconstructing the EFI was the only way for me to get things going.. And since I'm dual booting, the EFI had the boot information of both. Now, make no mistake. My Bootloader was backed up but I couldn't find a way to construct the EFI. Hopefully this helps someone.

The guide I followed:
http://www.eightforums.com/general-support/52515-windows-8-cant-start-due-missing-efi-partition.html


Requirements:---
--There can not be unallocated free space other than the one that will be used to create the partition. (200mb minimum)
--It must be the 1 in the boot order.
--It must be labeled as EFI
--Windows is needed (Install disk/USB )
--Working UNIBEAST USB is needed to do some emergency booting.


(Given the fact that my EFI was borked, I was unable to reboot into Windows as well.)


*Insert Windows Recovery Disk
*Advanced Recovery tools
*CMD
Commands to be written in the following order:
Diskpart
List disk
Select disk 0 (May be different for others)
Create partition efi
List partition (to verify that it was created and if it is on the very top)
format quick fs=fat32 label="EFI"


A hidden system partition will be created labeled 'EFI'
*Using your UNIBEAST USB, enter your OS X partition.
*Remove USB


Verify that is working---
Clover Configurator > Mount EFI
(The partition should be mounted with no errors.)


Re-Install Boot Loader on to the hard drive with the post-install tools.


If restoring: Drag your EFI folder into the EFI partition and replace its contents after installing post-install tools.


Reboot---
EFI should be working properly now.

**Feel free to move this to the appropriate section if this is the wrong place.

I had the same issue, messed up EFI Partition, but somehow recreated it using the following command in Sierra.

#newfs_msdos -v EFI -F 32 /dev/rdisk0s1

But Disk Utility still complaints corrupted partition map upon running First Aid.

#Checking prerequisites
#Checking the partition list
#Checking the partition map size
#Checking for an EFI system partition
#Problems were found with the partition map which might prevent booting
#Operation successful.

I have a non-UEFI Motherboard. I am using only macOS Sierra with Enoch Bootloader, no Windows. But has Windows 7/8/10/ Bootdisk.
How can I delete this partition to follow your guide to restore a pure EFI partition without loosing data on other partitions ?