I have multiboot on both my desktop and laptop, both have Windows 10 and EOS installed. One is a BIOS system installation, the other is a UEFi system. The desktop has grub installed in the MBR and the other has ESP. I updated Windows 10 to version 22h2 on both. On a desktop computer with BIOS, the bootloader remained unaffected by grub. On the other hand, grub rescue was received after the Windows release update on the UEFI laptop. I was able to start Kubuntu from the BIOS, on which I first installed its own grub, and after starting the machine with Kubuntu’s grub, entering EOS, I installed the EOS grub. The opposite was expected. What was your experience in this case?
This is commonly reported because Windows tends to overwrite data on the EFI partition during updates or installation. In years past, folks would have to reinstall Grub after every Windows update. It seems to have gotten better over the years, or perhaps I just hear it reported less frequently. But yes, what you are describing is pretty much normal.
In a UEFI system and in a dualboot Linux-Windows, perhaps the best practice would be to give each OS its own ESP in order to eliminate any possibility of interference.
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I rather read about the subject on various forums that it is entirely possible for GRUB to be overwritten after a Windows version update on BIOS machines, whereas on UEFI machines, the bootloader remains unchanged in the vast majority of cases. By the way, there is also a video about how to restore the original grub menu in grub rescue in such a case.
Yes, I thought about this before, but after installing Windows, when installing Linux, it usually doesn’t occur to people. It is also true that I have only recently started to install other OSes in multiboot on UEFI systems, until now the BIOS system was more typical for me.
PS. It is said that it is also not a safe method to create an ESP partition for each operating system separately, because there are machines with UEFI systems that only support one ESP. Instead, a directory entry must be created for each operating system in the /boot/EFI/efi directory. I saw that I have this with MX Linux.
You mean that there are some implementations of the UEFI in ceratian machines that looks for the bootloader in one and only one ESP on the disk?
I have (had) several computers of different make and models. All UEFI systems with GPT disks.
Whenever I have had any dual or multi -boot systems, I have almost always created an ESP for each OS.
And what is not safe about it when you say "it is said that it is also not safe …?
Could you elaborate more what it is said? What are the implications of having several ESPs for safety? Any source I can read about this?
By the way, I have had MX Linux in a multiboot system (Fedora, openSUSE, Linux Mint, Mx Linux) each with its own ESP. No issues I could remember.
Based on my personal experience, I’m afraid I cannot confirm what you are describing.
Probably also “unsafe to duel boot” there are a lot of things condsidered unsafe but as long a the user is aware a lot of this can be “ignored” just be aware of what you are running, why you are running it and make sure you are aware of anything security related. If these security issues are an issue for you don’t run and if you don’t know how to fix or securer than you probably shouldn’t be running what you are running or asking a system adim for help
At least there was an experienced user who reported such an experience, if I understood correctly.
Anyway, I had time now and played with the settings. On my Lenovo laptop, I installed grub on MX and disabled os-prober on Kubuntu. Thus, it is expected that Kubuntu grub package updates will not corrupt EOS-related kernel entries (initrd or initramfs). On the other hand, the os-prober run on MX left these kernel entries nicely intact. So I can always use the original EOS grub, but also the MX one if I like. And if something happens to the system startup, say due to a Windows version update, there is still the option of UEFI boot.
Thanks for the link!
Frankly, I find the statement “A lot of UEFI implementations, do not allow more than one ESP per device.” rather vague.
We don’t know to what extent these only-one-ESP-per-device UEFI firmwares are implemented on the numerous makes and models of computers.
Again, I can only talk to my experience as I mentioned above.
Also when it comes to “safety”, I think an argument can be made that having separate ESP for each OS is safer. Having only one means that it can be mounted and written to by all the OS:s on the same multiboot system thus a bigger risk that something gets messed up. At least this can be true in those cases when a Windows upgrade has overwritten other bootloaders in a shared ESP.
It makes perfect sense for each system to use its own ESP partition. But I think the quoted user also wrote what he wrote from experience. There are several ways to avoid possible grub errors. It is also possible to have a separate entry for each operating system in the /boot/efi/efi directory. Finally, booting into the UEFI BIOS itself is an option. What’s more, the installation of several types of Linux operating systems in multiboot is also good because if the usual system boot fails for some reason, we can start the machine with the other one, and we don’t need a live USB/cd. In my case, for example, I usually configure from MX Linux in such cases.