After lots of Try+Error, I can provide some more information about the problem. So here how I did another install with more information:
1. install is with ubuntu-26.04-live-server-amd64.iso 2. The first reboot (while installing, after late-commands but before user-data/runcmd) succeeds with initrd.img-7.0.0-14generic (size about 61kB). 3. I then run "apt-get update;apt-get full-upgrade" and kernel 7.0.0-29-generic is installed. Bot for some reason I don't understand, grub is not configured to boot this new kernel. Old 7.0.0.-14-generic is still booted. 4. Thus, I run "update-grub". This generates a much bigger (about 90kB) initrd.img-7.0.0-29-generic and configures grub to boot the 29-kernel. But this initrd will no longer start cryptsetup to unlock the rootfs. So the system is no longer bootable. 5. But I can unlock system from initramfs prompt by running "cryptsetup luksOpen /dev/nvme0n1pX cr-root" and can successfully boot the system by typing CTRL-D to quit initramfs environment. 6. So I decided to compare the two inird images to see whether I can make any clue what has changed. They appear to be completely different: in inird.img-7.0.0-14-generic, /init is a symlink to systemd while in initrd.img-7.0.0-29-generic /init is a shellscript. 7. From google, I got the information that there was a transition from initramfs-tools to dracut in ubuntu-25.10. So I did "dracut --force". This generated a new inird.img-7.0.0-29-generic with about 61kB. And THIS ONE was asking me again for the password to unlock the rootfs! 8. After a while initrd.img-7.0.0-29-generic wwas AGAIN 91kB in size and was no loger able to unlock the rootfs. I have no idea what triggered this regeneration and why it was big again. 9. I run "dracut --force" again, and it is again 61kB in size an boots the system happily. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2162931 Title: LUKS crypted root can not be opened during initrd To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/2162931/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
