How to repair the EFI boot configuration for OSX?

Question

I tried to set up triple boot (OSX + Win10 + Ubuntu) on my MacBook Pro. I messed something up, because now I cannot get back into OSX.

If I start the machine, I get the grub menu, and I can get into Ubuntu.

If I hold the Command button, then I get into the Mac boot selector (is that Boot Camp?), but I only see one option, "Windows", and the one for OSX (it used to be there with the name "Macintosh HD" or similar) is not there any more.

At some point I had to reinstall Ubuntu to be able to boot into something, because I cannot boot into Windows either, it displays a startup error during booting.
One thing I double-checked during installing Ubuntu again, is that the OSX partition is still there.

How can I repair the boot configuration from Ubuntu to be able to get back to OSX?

Answer 1

Well, I hope you solved your problem by now. But for anyone who might have this same problem you might start by opening /boot/efi in Ununtu there you could look for a backup of your OSX efi file. If found I guess it would need to be copied back in it's default location. If not then maybe there is a way to run a boot repair from an installation disk.