I had the same exact issue with my box. First couldn't update to 2.7.2 from 2.7.0 due to a bug with cert hashes. Had to run certctl rehash to update then after the update it wouldn't boot with no real error message. Luckily I stumbled on this thread. I was surprised to find that indeed using boot menu options 7 5 5 1 1 booted fine, but as they said above it's an every boot thing. My Lenovo M90q doesn't have a serial port so I attached a USB serial port which didn't do anything. In the end I updated my BIOS and it boots right up every time. Must be a UEFI bug that was patched.