Arch Linux Bricks Dual Boot With One Kernel Change

Key Takeaways

I can certainly see the value in dual booting multiple operating systems but when it comes to dual booting multiple Linux distros I just don't really see the value add especially when one of those distros happens to be Arch Linux but I'm not here to say whether you should or shouldn't some people out there do and a certain configuration is causing this to happen when you try to boot into Arch Linux error kernel doesn't support EFI Handover error you need to load the kernel first if I press any key I'm redirected to Grub and what's Curious is this isn't just a dual boot issue it's also happening with single boots of Arch Linux using sys Linux as a UEFI bootloader yes you can do that no you shouldn't and considering how small both of these groups are it's no surprise that hardly anyone is talking about this but it is a really serious issue if you are having this issue you literally cannot boot into Arch however we do know exactly when and why this problem happened it all began with the update to the Linux 6.2 kernel and it all happened because of a single line config change and depending on how you want to frame it how nice you want to be to the arch team this may or may not be their fault more on that later but let's get into what the problem actually is so a few years back a feature of the kernel was marked as deprecated that feature being the EFI Handover protocol you might remember that from appearing inside the error message so the EFI Handover protocol was first added into the kernel all the way back in the Linux 3.6 update roughly a decade or so ago right now EFI bootloaders and the EFI boot stub in the Linux kernel carry the same initialization code to set up an EFI machine for booting the kernel however with this EFI Handover protocol support this redundant code could be eliminated Intel and others want to have the initialization and boosting of the kernel just within the Kernel's EFI boot stuff then also copied within the bootloader the Linux 3.6 kernel provides the Handover protocol support on the Kernel side but the EFI bootloaders need to be updated to support the EFI Handover protocol entry point when they do have this support the responsibility of EFI bootloaders come down to just loading the kernel image from the boot media and providing any user interface for boot menu options EG selecting different kernels so at the time it certainly seemed like a much better option but it also needed support from the bootload aside and this is where the problem happened this protocol has no basis in the UEFI specification and there are better ways to pass additional data to a UEFI application UEFI configuration tables UEFI variables ufi protocols then going around the site image boot service and jump into a fixed offset in the loaded image just to call a different function that takes a third parameter given that loaders such as grub already carry the boot param's handling in order to implement non-efi boot retaining that code and just passing boot params the EFI stub was a reasonable choice although defining an alternate entry point could have been avoided however the grub slide changes never made it Upstream in the meantime EFI support has been added to other Linux architecture ports as well as to you boot and systemd including architecture agnostic methods for passing a knit Rd images in memory and for doing mixed and for doing mixed boot mode none of them requiring anything like the EFI Handover protocol so since none of the projects that matter are using your upstream and it's already marked as deprecated let's also just make it optional now they can't just go on remove it because the kernels and like to generally break things that are in use and even though these patches aren't Upstream they are being shipped by some Downstream distros when they say some a lot of the major distros like Ubuntu open Susa things like that but if for whatever reason you do want to get rid of of it when compiling of the kernel all you need to do is change EFI Handover protocol from y to n by default support is going to be compiled in however the Arch Linux team decided to set it to no and they do have good reason for doing this from their perspective it makes complete sense the vanilla version of grub the version of grub they ship on their distro does not support EFI Handover protocol Arch Linux does not ship those patches so the theory is if Arch linux's bootloader doesn't make use of the EFI Handover protocol there is literally zero harm in removing it from the Arch Linux kernel and much like the Flat Earth that theory isn't exactly correct I already mentioned that distros like open Susa and Ubuntu ship these patches not only do they ship these patches because their kernels are always going to have the EFI Handover protocol enabled grub expects it to be enabled in the kernel it's receiving and if it's not like in the case of the Arch Linux kernel well people are going to report the bug on those distress as well this is a report over on tumbleweed and this is the same report over on Ubuntu grub relies on optional deprecated EFA Handover protocol and at least in the case of Ubuntu they have no plans to change anything this is expected yes and there isn't anything we can do about this for the foreseeable future this is not Ubuntu specific all big distros use the Handover protocol and also Enterprise distributions will likely have to continue to do so for the foreseeable future due to external obligations that I can't go into further detail about effect actively what has happened here is a soft Fork of grub has become the default version most of the districts out there are not shipping the grub that comes from the Upstream distro they are using these red hat patches this is why I said you can choose whether you want to blame Arch or not technically Arch is doing what Upstream expects to be done the issue is that no one else is so you either conform with upstream or you can form with the standard that other distros are doing how you want to look at that depends on where you want to place your blame now this is where the problem gets really cool the problem only happens in One Direction so if you're using the Ubuntu version of grub this expects EFI Handover protocol to be enabled so the Ubuntu kernel will boot just fine but the arch one won't the arch one doesn't have the protocol enabled but the same isn't true if you're using the arch version of grub the arch version does not expect to be enabled it doesn't even use it but it can still boot Ubuntu no problem whatsoever and can also boot Arch the exact same so the easiest and most permanent solution is stop using grub from distros that are not Arch if you're dual booting with Arch use the arch version of grub this is the vanilla version and it's gonna give you the better experience at least in this case now as for sys Linux please for the love of God do not use syslinux on a UEFI system better yet don't use CIS Linux the project is long dead and is having lots of issues with modern systems but if you do when I said there are no boot loaders that matter that use the EFI Handover protocol I meant that on purpose because CIS Linux does actually use it it just doesn't matter so now that uh now the arch kernel doesn't you you just can't boot UEFI systems using sys Linux with the arch kernel uh for the record CIS Linux is in the core repos I would fully support dropping this down into the Aur if it literally cannot be used with the mainline Arch kernels so the solution to that is the same solution from before stop doing that just use a normal bootloader use the version of grub from Arch Linux or use another bootloader but use the version from Arch Linux and also please if you report a bug that has to do with booting please just mention if you use CIS Linux this led to a giant thread with people trying to work out what the problem was doing get bisex and everyone just assumed this person was using grub they weren't um probably would have been better to mention which bootload you were using from the outset CIS Linux development hasn't been updated in years so it's no wonder there are issues when using it to boot Modern Hardware for your information sys Linux is considered basically dead by some folks I think by most folks but sure sums technically correct as well from what I've seen there's not really a discussion about what to do with the EFI Handover protocol one person here does give a pretty good answer though so this post here which is the optional enabling thing specifically suggests people should set this to why if in doubt doesn't seem like this will be removed anytime soon probably won't be considering how useful it is with uh some of the Enterprise systems no reason not to just have this enabled in the Arch Linux kernel configs this is breaking installs for no good reason right now and I I think that just sums it up well there's not really any benefit in getting rid of it but there is a pretty big drawback and that's for all of the people using bootloaders from distros that are not Arch so re-enabling it just seems like the easiest thing to do but let me know considering how small both these groups are dual booters using a bootloader from another distro and CIS Linux users do you think the arch team should even bother to go and change anything back maybe like you know 50 or 100 people are actually going to be affected I would love to know do you happen to use one of these systems maybe it's more people than I thought get a little bit better let me know your thoughts and down below I'm not going to cut that we're just going to leave that in there uh it's gonna be it for me if you like the video like the video If you really liked the video and you want to become one of these amazing people over here patreon scrub cell bear pay down below that's gonna be it for me and outro of some sort [Applause] [Music]