For now I'm just writing down some of my random thoughts, but looking at Daniel's diff between the working image and non-working, I don't see anything straightforward that could have caused it. That being said, Dimitri had a good idea that one of the livecd-rootfs changes could have caused it. I now see this which might be somehow related?
https://launchpad.net/ubuntu/+source/livecd-rootfs/2.528 Time-wise it could fit, as the package - even though uploaded on the 28th of May, it actually only migrated from cosmic-proposed to cosmic on the 5th of June (our images are built without -proposed enabled). Need to look into the change itself, but it does deal with grub somehow. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1775743 Title: [regression] Cosmic daily images 20180606-11 install but boots only to grub prompt on EFI systems To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1775743/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs