We discussed this a bit upstream and we believe this to be random, and not a regression in those later 15.4 updates.
Apparently there is a buffer overflow in shim that makes it override memory of other EFI components, and depending on where that triggers, it can cause all sorts of random boot failures. The fix for that, https://github.com/rhboot/shim/pull/365, has been merged for the upcoming 15.5 shim release. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1936759 Title: shim-signed 1.48+15.4-0ubuntu5 does not secure boot To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/shim-signed/+bug/1936759/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
