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[Solved] Clean install EFI wipe?

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I recently decided to do a clean install of High Sierra and have noticed that the EFI partition and its contents seems to remain even after erasing the drive on which it resides. How do I wipe the target installation disk of all partitions/volumes before installing High Sierra?
 
I recently decided to do a clean install of High Sierra and have noticed that the EFI partition and its contents seems to remain even after erasing the drive on which it resides. How do I wipe the target installation disk of all partitions/volumes before installing High Sierra?
  • You really don't have to do that to install High Sierra on the disk.
    • The Disk Utility of your HIGH SIERRA USB installer, when it reaches the Installation screen >Disk Utility , can do Erase to do the needful and during installation , will use the system partition to copy the High Sierra to it. Later Multibeast when used choosing Quick Start or Bootloaders tab will overwrite whatever file s were there in the EFI Partition and create a new EFI folder to install CLOVER.
  • If you really want to know for any other reason how to delete existing EFI partition:
  • You can use Mac/Windows10/Linux
  • I will just give you steps in Mac Terminal first:
    • Attach the disk to a Mac /Hack either using SATA or SATA-USB adapter;then it will act as a USB device for this purpose)
  • Launch Terminal
  • cmd diskutil list [ENTER]
    • This will list all disk attached to the system
    • From the output locate your disk by its size and its existing file system
    • Locate your disk's "IDENTIFIER"(Last column in the output) find its disk number [Example: /disk1] You may have a different disk ID
      • next you want to unmount that disk whose EFI you want to delete]
    • diskutil unmountDisk /dev/disk1
      • To delete the EFI partition of that disk use the command
    • sudo gpt remove -i 1 disk1
Type admin password on prompt and ENTER
Terminal will confirm cmd execution.[disk1s1 removed]

In Windows 10:

Search >cmd Right click >Command Prompt>Run as Administrator>
Following prompt appears
C:\Windows\System32>
> C:\Windows\System32>diskpart [ENTER]
DISKPART>
Type command list disk
DISKPART> list disk
All disks will be listed
Locate your disk's number [Example 2]
DiskPART>Select disk 2
Disk 2 is now the selected disk
Diskpart> Clean
That will clean all partitions.
 
Thanks for the quick response.

I've got one more question though. You mentioned that multibeast will overwrite any files found in the EFI volume when performing the boot loader installation. How is it then that the bootloader theme I downloaded and chose with my previous installation keeps presenting itself on boot? It seems my config.plst is preserved, which is why I was contemplating ways to wipe the EFI partition to ensure no settings/kexts/etc from a previous installation would affect the new one.
 
Thanks for the quick response.

I've got one more question though. You mentioned that multibeast will overwrite any files found in the EFI volume when performing the boot loader installation. How is it then that the bootloader theme I downloaded and chose with my previous installation keeps presenting itself on boot? It seems my config.plst is preserved, which is why I was contemplating ways to wipe the EFI partition to ensure no settings/kexts/etc from a previous installation would affect the new one.

  • Is that theme one of the themes offered by current Multibeast's Clover?
    • Without seeing that theme and the Version of MB you have used, I cannot comment on your experience with Multibeat installation and the choices you have made.
    • As far as Clover is concerned, all that MB does is to install a version of Clover as UEFI or Legacy used in that build of MBeast.
      • It is similar to your own use of the same Clover version as a Stand alone downloaded from the Sourceforge.net but made a lot easier.

  • If you delete the EFI partition in Terminal diskutil command as previously posted, and then create a new in GPT scheme using diskutil command, that newly created EFI partition will be empty when mounted using an EFI mounter command or app all previous files will be deleted.
  • I hope this answers your question.
 
  • Is that theme one of the themes offered by current Multibeast's Clover?
    • As far as Clover is concerned, all that MB does is to install a version of Clover as UEFI or Legacy used in that build of MBeast.
      • It is similar to your own use of the same Clover version as a Stand alone downloaded from the Sourceforge.net but made a lot easier.
  • If you delete the EFI partition in Terminal diskutil command as previously posted, and then create a new in GPT scheme using diskutil command, that newly created EFI partition will be empty when mounted using an EFI mounter command or app all previous files will be deleted.
  • I hope this answers your question.

Hello @cmn699
I ran into similar issue/question here.
I want to have a fresh install of HS in my machine. After several install using USB boot disk created using UniBeast, I found out that the settings of macOS is the same with previous install. What seems to be different is the SMBIOS. Even Rt Variables are still same with previous install.
Thus I am thinking of deletin the EFI.
Instead of formatting, can I just delete whatever the file inside the EFI using finder, restart the machine, and install new one from boot diak I have of my previous install? Will thus achieve the expected result of real fresh new HS with fresh settings?
Thanks.
 
Hello @cmn699
I ran into similar issue/question here.
I want to have a fresh install of HS in my machine. After several install using USB boot disk created using UniBeast, I found out that the settings of macOS is the same with previous install. What seems to be different is the SMBIOS. Even Rt Variables are still same with previous install.
Thus I am thinking of deletin the EFI.
Instead of formatting, can I just delete whatever the file inside the EFI using finder, restart the machine, and install new one from boot diak I have of my previous install? Will thus achieve the expected result of real fresh new HS with fresh settings?
Thanks.

I don't know if I understood you right.
If you just want the contents of EFI partition deleted and create new content, yes you can do that.
But I guess you need to know that the EFI Partition is HIDDEN. You cannot just use a Search & Find tool for that.
You have to 'unhide" EFI partition of the disk in which it is created during Erase Disk tool in Disk Utility.
The Disk Utility selects the first 200+MB of the disk and makes it EFI partition. If you don't further partition that disk it will leave all of the rest of the disk to save your macOS Sierra with a smaller portion for Recovery Partition or Recover HD.
The 200MB EFI is set aside for the Bootloader CLOVER.
If you are using Unibeast to install your macOS on a hard disk so created, it will copy all the macOS Sierra files to the larger Partition in the 30-45 minutes
Unibeast DOES NOT install its CLOVER in the hard disks' EFI Partition.
The System disk created by Unibeast (or terminal command) will not boot as it has No Clover bootloader.

You need Multibeast to find the EFI partition and Create an EFI folder and place CLOVER in it.

To create that CLOVER to boot in Legacy or UEFI mode, you need to specify that choice up front in the Multibeast.

Multibeast will also give you a chance to select what ever kexts you think your motherboard's Audio/Ethernet/USB hub etc needs based on its Chipset for these devices. Multibeast CANNOT DECIDE what your MoBo needs for its kexts. YOU have to know this before you ever start to build and then from the various Menus inside Multibeast, find what you need.
I have seen many complaining about Multibeast for their failure to find their MoBo's Documentation to decide what drivers they need. Multibeast has a large number of menu options to choose from; but it has no way of sniffing out from your MoBo chips and provide the kexts needed for those devices

It also has menu to select the SMBIOS Name for your system. This selection is generally provided by MB as the most widely 'acceptable' imac14,2, but NOT ALWAYS the right one for all the myriads of MoBos.

Once Multibeast finishes all these steps, it will mount the EFI Partition of the hard disk on the Desktop .

This is the only time you are going to see EFI Partition mounted automatically on the desktop.

At this time you can use your mouse and keyboard to go inside EFI Folder and find the CLOVER folder, Copy and keep it in some place if you like or edit its contents whatever way you want provided you know what you are doing.

You can delete or add files to its kexts/Other and remove empty unwanted numbered folders inside /CLOVER/kexts like 10.6 to 10.13

You can open config.plist in an editor you are comfortable with (but not TextEdit) like Clover Configurator Vibrant (CCV) to edit the various menus of config.plist if you know what you are doing or you have been getting expert help .

But once you shut down or Reboot the computer , you cannot find EFI any longer . It will be hidden by the system to protect its bootloader from accidental deletion.

After this, if you ever want to change anything inside EFI , you got to mount the hidden EFI Partition on the Desktop.
You can use EFI Mounter V3 to mount it but it is not an editor you can use for config.plist .
CCV is an EFI Mounter and Editor in one tool.

Thus I am thinking of deletin the EFI.
Instead of formatting, can I just delete whatever the file inside the EFI using finder, restart the machine, and install new one from boot diak I have of my previous install? Will thus achieve the expected result of real fresh new HS with fresh settings?
Thanks.

Remember : without CLOVER and its properly installed contents, No disk can boot in macOS the way we create in this Forum ( I am not talking about any other bootloaders-ONLY CLOVER)

Do NOT do what you plan to do the way you have phrased it.
 
Last edited:
I don't know if I understood you right.
If you just want the contents of EFI partition deleted and create new content, yes you can do that.
But once you shut down or Reboot the computer , you cannot find EFI any longer . It will be hidden by the system to protect is bootloader from accidental deletion.

After this, if you ever want to change anything inside EFI , you got to mount the hidden EFI Partition on the Desktop.
You can use EFI Mounter V3 to mount it but it is not an editor you can use for config.plist . CCV is an EFI Mounter and Editor in one tool.


Remember : without CLOVER and its properly installed contents, No disk can boot in macOS the way we create in this Forum ( I am not talking about any other bootloaders-ONLY CLOVER)

Do NOT do what you plan to do the way you have phrased it.

Hello @cmn699
Thank you very much for the detailed explanation and warning.
Yes, I am noob on this hackintosh environment, thus need very much this kind of explanation.
For now, I have not do any modification as such to my EFI. Your explanation will be my future reference when I want to do such things in the future. Also, a guide for me in better understanding the EFI.
Thanks again.
 
Hello @cmn699
Thank you very much for the detailed explanation and warning.
Yes, I am noob on this hackintosh environment, thus need very much this kind of explanation.
For now, I have not do any modification as such to my EFI. Your explanation will be my future reference when I want to do such things in the future. Also, a guide for me in better understanding the EFI.
Thanks again.
Thank you.
:)
Sorry for my typos in the write up. I will edit and tidy them up.
 
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