<div dir="ltr">I think running at install time and caching the output somewhere makes sense for most cases. You can create some documentation on how to re-run it at manually to regenerate that output if you have consciously added another operating system and want to detect it one off.</div> <div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Dec 17, 2021 at 10:03 AM Julian Andres Klode <<a href="mailto:julian.klode@canonical.com">julian.klode@canonical.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi ubuntu-devel, os-prober is disabled with the grub 2.06 upload, which is obviously a bit controversial and the outcome is not necessarily in the best interest of our users. # Reasons os-prober is inherently insecure as it mounts all partitions on your disk using grub-mount to check them for other OS, which is not a nice thing to do as root as you can exploit bugs in the filesystem code easily. # Outcome 1. Users on UEFI are unable to boot other Ubuntu installs, but can boot other OS via the UEFI bootloader. Multiple Ubuntu installs are a hack either way, so not really a huge priority - any Ubuntu install installs grub to the same location, so your grub just switches between your Ubuntu installs each time you upgrade it in one. Ugh. 2. Users on BIOS systems cannot boot any other system This is highly problematic # Options 0. Re-enable os-prober 1. Red Hat only runs os-prober during install time, and instead of regenerating grub.cfg when kernels are installed writes out drop-in files that are then loaded (it actually uses the systemd-boot load entries format, which it has patched into grub) We could run os-prober during install time, store the output somewhere and then reuse the cached output in grub-mkconfig. 2. Can we have an "Other Boot options" entry that goes to the UEFI boot menu? Or, write a grub module that goes through the UEFI boot options and creates a submenu, then sets BootNext and resets the machine when you select an item. 3. Detect the presence of Windows inside grub.cfg and allow chainloading that, to handle the major dual-boot use case. 4. There was some initial code for a basic os-prober reimplementation at boot time, which avoids the security issues of running os-prober at run-time, but also that's a bit meh. -- debian developer - <a href="http://deb.li/jak" rel="noreferrer" target="_blank">deb.li/jak</a> | <a href="http://jak-linux.org" rel="noreferrer" target="_blank">jak-linux.org</a> - free software dev ubuntu core developer i speak de, en -- ubuntu-devel mailing list <a href="mailto:ubuntu-devel@lists.ubuntu.com" target="_blank">ubuntu-devel@lists.ubuntu.com</a> Modify settings or unsubscribe at: <a href="https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel" rel="noreferrer" target="_blank">https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel</a> </blockquote></div> <div> </div>-- <div dir="ltr" class="gmail_signature">Mario Limonciello <a href="mailto:superm1@gmail.com" target="_blank">superm1@gmail.com</a></div>