Disable kernel signature checks during boot on Ubuntu?

Hi Everyone, Ubuntu provided 5.0.0-27-generic today. I attempted to reboot but booting fails due to a failed signature check. I'd like to tell the kernel to skip the signature check during boot. I found Ubuntu's UEFI | SecureBoot | DKMS (https://wiki.ubuntu.com/UEFI/SecureBoot/DKMS) wiki page. It discusses several ways to disable signature checks but they assume a working machine. I'm at the grub boot menu with the menu open ready for editing. What option should I use to disable the signature checks during boot? Thanks in advance, Jeff