Make EFI Bootable Error "Change Bootable Error"


#1

You’ll probably laugh at me for what I’m attempting to do with my 2018 13" MacBook Pro:

I have my old PC NVMe drive (960 Evo) with Windows 10 installed (the very installation I was running on my old PC) attached to an external adaptor, and I am trying to see if I can boot into windows externally from this. My Mac computer recognizes it as a drive, but it only shows as a folder icon in the startup manager. I had the issue with Startup Disk claiming I cannot boot from said drive (the ‘bless tool’ was unable to set the boot disk). I read someone using Winclone to solve said issue by making the drive EFI bootable. I tried to do this with my drive, however I encounter “Change Bootable Error”. I disabled the csrutil in the recovery terminal, and allowed external booting in the recovery terminal as well. I’ve attached a screenshot with some information if useful at all.

Any help is appreciated. Thanks!


#2

Winclone assumes the EFI partition is the first partition, and yours is the second partition. It might be possible to take a Winclone image of it, then wipe and recreate the GPT format, then restore the image. Make sure you have a good backup first, since it might all fail spectacularly.

tim