On Tuesday, 10 February 2026 11:13:42 Greenwich Mean Time Nuno Silva wrote: > On 2026-02-10, [email protected] wrote: > > Greetings, > > > > I've just finished installing a new system, choosing systemd-boot > > rather than grub. The handbook says that /etc/kernel/cmdline should > > contain 'quiet splash', but that's clearly not the whole story so I > > improvised. > > (Speaking of what ends up being fed to linux, IIRCWOC* it can indeed > be made shorter if the defaults are appropriate (I think I've used > the kernel .config default commandline setting to set hibernation > resume partitions and boot partitions before, for example.) > > * IIRC WithOut Caffeine > > > 'blkid | grep nvme0n1p5' shows this: > > > > /dev/nvme0n1p5: LABEL="RootFS" > > UUID="7ab169d9-03cb-44ce-98f6-1955c2458a4c" BLOCK_SIZE="4096" > > TYPE="ext4" PARTLABEL="root" > > PARTUUID="aeb1b1eb-7995-44ac-84ad-0e999ff4459d" > > > > ...so I put this into /etc/kernel/cmdline: > > > > root=UUID=7ab169d9-03cb-44ce-98f6-1955c2458a4c quiet splash > > > > Then on rebooting, I get 'Cannot open blockdev' or similar. > > > > Should there be some punctuation in my command line? Or perhaps I > > should have specified the PARTUUID instead of the device UUID. This > > is one of the few places where the handbook doesn't show an > > example. > > > > I can't check online at the moment because the site's down. > > I know from experience that PARTUUID works at least for "MSDOS"/"MBR" > partition tables. > > Now I have the faint recollection that there was some kind of id-based > approach that required udev to be running - but maybe that'd be just > the /dev path with ID. (In such cases, I think it'd have to be used > with an initrd?) Or maybe it was only necessary for MBR partition > tables and would still work with e.g. GPT?
root=PARTUUID=XXXXXXXX should do the trick. If you don't change your root partition block device regularly you can specify it in the kernel itself. Look at the CONFIG_CMDLINE option.
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