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I recently installed Fedora 18 using EFI boot. Like the other current linux distributions, it sets up GRUB2 for me.
I have experience with re-installing the BIOS version of GRUB when things go wrong. I know e.g. how to boot a rescue disc, chroot into the installed system, run grub-install
and possibly update-grub
/ grubby
/ grub-mkconfig
.
How would I reinstall the EFI version of GRUB when things go wrong? (I know things will go wrong: I break them).
Why have you asked a vague question and then immediately answered it? Although the answer provides useful information, the question really needs elucidation: Knowing you changed something is not sufficient. Understanding precisely what was changed is really necessary to provide a good response to the question. – Rod Smith – 2013-05-16T17:35:46.547
@RodSmith thanks for replying to my email about EFI earlier :). And for adding your comment to the downvotes. The question I started with was literally this. I'm experienced with re-installing grub-pc. I want to have the same level of confidence, that I know how to recover an EFI system. I editted the question once to emphasize that it was about reinstalling grub... I guess I should try again and be more explicit about my motive. – sourcejedi – 2013-05-17T07:44:31.967
Why are you using grub if you have UEFI? What advantage does chaining the two boot loaders provide? – Marco – 2013-05-17T07:59:06.927
@Marco UEFI is not the boot loader supported by any linux distribution I know! Fedora updates GRUB automatically when it installs a new kernel, and installs necessary boot options like root=. It doesn't do that for EFI. I could abandon distribution support & use REFIND's automatic scanning w/ kernel options in refind.conf, but that would still be chaining boot loader/managers! And Microsoft don't sign GPL drivers, so Secure Boot has to go SHIM->boot loader->Linux anyway, and you really want a boot menu after the UEFI->SHIM part.
– sourcejedi – 2013-05-17T08:18:20.470After installing a new kernel a single call to
efibootmgr
is sufficient to update the entry in the UEFI menu. I don't know about rEFInd or SHIM. I personally don't chain multiple boot loaders. All operating systems are added to the UEFI boot menu and it's working perfectly fine. – Marco – 2013-05-17T08:32:59.063