Go to the hyperlink which Steve has mentioned and install the kernel. Then boot choosing the newly installed kernel option and go to recovery mode and upgrade your grub. Again reboot but choose the 4.15 kernel. And update. the shim package is installed.
I dont know the technical details as to what was the problem but my 18.04 ubuntu is working fine now. The apt-get upgrade option does not mention the error code. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1767276 Title: Could not delete variable: Interrupted system call (package shim- signed 1.34.9+13-0ubuntu2 failed to install/upgrade: installed shim- signed package post-installation script subprocess returned error exit status 1) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/shim-signed/+bug/1767276/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
