https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/sec-reinstalling_grub_2

i nuked my grub, is this guide safe? rm-ing anything I don't understand entirely is scary

@synthgal looks fine to me assuming you're using redhat or equivalent

@troubleMoney should I -r that first rm command?

@synthgal do it as written

@troubleMoney it's giving me "cannot remove, (x) is a directory" errors

@synthgal hm, you can probably ignore those, grub only looks for files with a number in front of them IIRC

Probably best to keep to the guide, the one who wrote that knows more than I do about it

@troubleMoney christ, I think this guide assumes I have a network connection because I have to yum stuff :D

@synthgal oh yeah, that would indeed be an assumption, yeah

@troubleMoney thank you based Sam

had to do a little DNS stuff but nmtui was a lifesaver

@synthgal oh god yeah, nmtui is super useful and good

@troubleMoney okay hopefully last question

since I'm using centos and not redhat, would I change /boot/efi/EFI/redhat/grub.cfg to /boot/efi/EFI/centos/grub.cfg?

Other grub guides explicity for centos do it this way but it's a deviation from the repair guide

@synthgal yeah, point it at the one with centos in it

@troubleMoney well that seemed to do nothing at all.

the rescue mode had me chroot to mount my partition, that woun't change anything?

@synthgal hang on, rescue mode? I thought you were just doing a reinstall

Okay that changes things substantially, sorry, should have realised that was what was going on

What's the current situation when you boot?

@troubleMoney the CentOS installation disk emergency shell is where I'm trying to do this from

@synthgal okay, cool, so you're chrooted in to your centos install? If you're not, then do so

then you'll want to do "/sbin/grub-install /dev/[your hard disk]", your hard disk will be in the form of hda or sda or something similar

After that check that there isn't anything obviously wrong in the /boot/grub/grub.conf file and reboot, that should fix it

@troubleMoney grub2-install: error: /usr/lib/grub/x86_64-efi/modinfo.sh doesn't exist. Please specify --target or --directory

@synthgal is grub2-efi-modules installed?

@troubleMoney it is now

@synthgal cool, if you try /sbin/grub-install /dev/[whatev] again it should hopefully find that file

@troubleMoney just to be clear, I want /dev/sda, not /dev/sdaX? isnt GRUB supposed to be in that boot partition with EFI?

@synthgal yeah, /dev/sda rather than /dev/sdaX

You want it in the master boot record of the disk you're booting from

@troubleMoney I thought UEFI didn't use MBR anymore? Sorry I'm just really paranoid

@synthgal Sorry, that's probably GPT rather than MBR these days

You want the bootloader on the drive you're using rather than in a partition is the long and short of it

@troubleMoney command not found, should I do grub2-install?

@synthgal that's the one I meant, yeah

@synthgal It's been a while since I mucked around with bootloaders and stuff, I keep remembering the older commands for things