@dreN Great! Are you currently using the dev-branch version? Testing/using the latest dev-branch and reporting issues if you can. As well you are more than welcome to help on the documentation. Please send me a private message to discuss further steps.
Did some more testing and will merge this into dev-branch now before the new release. Have tested on CentOS (existing installation and fresh) as well as Debian (fresh installation). Should be good to go.
@bloodwar I have looked through the code up and down, forth and back… Just don’t know all about UEFI and have no idea why this goes wrong. I am pretty close to sending a message to the kernel mailinglist. But before that I’d like you to try other kernels first. Please use some older kernels just to see if those can boot on that device. I think the easiest way is to download old kernel binaries here and here, plugin the USB key you made and put the kernel binary on it as EFI/BOOT/BOOTX64.EFI (rename that file - GRUB EFI binary).
Now boot the Lenovo N24 off that USB key and see how far you get. If you see Kernel Panic - not syncing: VFS: Unable to mount root fs on unknown-block(1,0)) than you are past the issue. If it just sits there for 3 minutes then I’d expect it to be locked. Please try at least 10 kernel binaries of various versions from the links above.
@sebastian-roth I found the error was only in regards to the checkbox. It worked the “first” login entry you make, but the modal window wasn’t closing. So you would press the delete button again, causing the invalid login (as it was at that point invalid as no credentials were being passed anymore).