hello,
I don’t know if this is the right place to ask this question but could someone explain me how a UEFI system boots, I couldn’t find a guide online. I want to know because I don’t understand certain GRUB commands and how it get installed.
I just copy paste commands from Arch wiki and it just magically works without me knowing anything about it.
all the different distros use different grub command parameter and it’s so confusing. eg, Arch and Gentoo.
Arch command: grub-install --target=x86_64-efi --efi-directory=esp --bootloader-id=GRUB Gentoo command: grub-install --efi-directory=/efi
why both command is different? exactly where does grub gets installed?
sorry if this is a naive question but i really don’t understnad GRUB.
What’s confusing, when x86 initializes it preloads specific address in IP motherboard manufacturer has BIOS there that sets up first 512 bytes. and IP jumps to the new address then it sets up rest of /boot and switches your CPU to real mode up until that point it was in 8bit mode now it is in 16 bit. then jumps to that, now it switches to protected mode I.e. 32bit and loads kernel and initramfs (to solve chicken and egg problem) and then your os boots.
Throw in cryptsetup and shim and switching to 64 bit somewhere there.
Yes, x86 legacy is really confusing. Especially if you are going to write your own kernel or bootloader.