Description of problem: During tests for https://bugzilla.redhat.com/show_bug.cgi?id=2159288 we found another grubenv configuration that could also make leapp upgrade fail. How reproducible: Always Steps to Reproduce: 1. Get a 7.9 machine, install leapp-upgrade, run leapp preupgrade until it has no inhibitors and the report is successful 2. cd into the directory where grubenv is located 3. execute: truncate --size=1023 grubenv echo -n 'a' >> grubenv 4. run leapp preupgrade (it does not inhibit) 5. run leapp upgrade (it works). 6. reboot Actual results: On reboot, the wrong grub entry is selected by default. If the correct entry is manually selected (upgrade initramfs), the machine ends up in emergency shell. Expected results: Inhibit leapp upgrade if such a format is found in grubenv. Additional info: Test MR (the test is already written and for now the test case will be commented out until this is resolved): https://gitlab.cee.redhat.com/oamg/leapp-tests/-/merge_requests/214