How can I update the kernel and initrd images in EFI boot loader?

Question

I have successfully installed the EFI boot loader (using ELILO) but I am unsure how to actually keep the kernel images up to date. Can you help me understand the process please? Thanks.

http://www.rodsbooks.com/efi-bootloaders/elilo.html

Answer 1

So, here's what the link says:

Maintaining ELILO

If your distribution includes scripts to maintain ELILO automatically, and if those scripts work, you shouldn't need to do much to maintain this boot loader. As noted earlier, though, in my experience these auto-maintenance scripts are often worse than useless. Thus, you may need to keep your ELILO configuration up to date when you upgrade your kernel or ELILO itself. This task involves copying the updated files to the ESP and making changes to elilo.conf.

If you install an updated kernel, I strongly recommend that you add that kernel to the ESP, and entries for it to your elilo.conf file, rather than replace working files and entries. Once you've rebooted into the new kernel, if you're satisfied that it works, you can delete the old kernel and initial RAM disk file and remove its entry from elilo.conf. If you delete these entries, and especially the files themselves, and the new ones don't work, you may find it difficult to boot your system to correct the problem. (One of the advantages of EFI, though, is that a full implementation includes a shell that you can use to edit configuration files and make changes, so some such problems can be easier to correct on an EFI system than on a BIOS system. In the EFI shell, type edit filename to edit the specified file.)

My interpretation is you need to re-do a good chunk of the install process.

Admittedly you won't have to re-copy elilo.efi. (Unlike original lilo you don't seem to need to run a lilo command under Linux to update the bootloader. I wonder if there is some command to check the syntax + filenames though!). You won't have to re-run efibootmgr either.

You will have to copy the new kernel and initrd over, and then edit elilo.conf to add a new entry. I would definitely keep at least one old entry unmodified, which would give you a recovery path from certain errors.

unsolicited ranting

This is why distributions provide scripts for your boot loader :-).

It can be argued that most kernel updates aren't critical. (Remote holes are rarer, more vulnerabilities are local privilege escalation bugs). AIUI Linux Mint developers favor this interpretation. So low-security systems might tolerate a reduced frequency of updates.

My interpretation is that you still want a regularity (or consistency) of updates. So a manual process would only be appropriate for a test-lab install, used for a specific purpose.

It would be great to have an answer here with pointers for an ELILO install with automatic maintenance. If you develop one you could post it :-). In their absence, this might tell you something about how useful ELILO is in current practice. Perhaps also about the train of thought that lead to you trying it, and contextualizing online sources. (And I'm being entirely hypocritical here, because I'm a complete nerd about learning such things myself).

The alternative rEFInd seems to have a few vocal fans on these boards. I believe it has been mentioned by my personal hero Matthew Garret... so watch this space... but he's been pouring even more blood into GRUB recently, so he might be soul-bound to that for a couple more eons.