On 10/19/25 11:36, Feli Flitzberg wrote: > Hi, long time watcher, first time poster. If the bootloader supports the > Discoverable Partitions Specification, all that's needed is the correct > partition GUID assigned to every partition. After that, you don't need to > pass any partitions or use /etc/fstab as the bootloader will read the disk it > came from to mount everything. The only major limitation is that your > bootloader partition MUST live on the same disk as root and usr, otherwise > they won't be found. Hope this helps!
How can the OS know which block device the system was booted from? > Feli Flitzberg > > https://uapi-group.org/specifications/specs/discoverable_partitions_specification/ > > Sent from Proton Mail for iOS. > > -------- Original Message -------- > On Saturday, 10/18/25 at 19:50 Demi Marie Obenour <[email protected]> > wrote: > This isn't systemd-specific, but I know that at least some systemd > developers recommend using UEFI secure boot + dm-verity, which leads > to this problem. I also don't know a better place to ask for help > on this. > > How do OSs using dm-verity and UKIs find the user data partition? > On some systems it is trivial, as the storage device it must be on > is known ahead of time. However, desktops and servers can have many > storage devices or even use RAID, making this very nontrivial. > > Non-immutable OSs generally store this information in either the > initramfs, root filesystem, or kernel command line. However, with > signed UKIs and dm-verity both the initramfs and root filesystem are > provided by the OS vendor and can't be changed. This means that one > must load the user data partition to be able to read any data one > has stored on disk, but one must read data stored by the installer > to find the user data partition. Circular dependency, whoops. > > What is the standard solution to this problem, if any? The only one I > have come up with is UEFI variable storage, but I'm curious if there > are others. > -- > Sincerely, > Demi Marie Obenour (she/her/hers) > -- Sincerely, Demi Marie Obenour (she/her/hers)
OpenPGP_0xB288B55FFF9C22C1.asc
Description: OpenPGP public key
OpenPGP_signature.asc
Description: OpenPGP digital signature
