Boot hangs when loading initial ramdisk

[jhoechtl]

Kernel 4.13.2 fails to boot. It stops after Grub printing "Loading initital ramdisk".
The last successful kernel which booted was

Linux ebola 4.10.0-32-generic #36~16.04.1-Ubuntu SMP Wed Aug 9 09:19:02 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

I edited Grub command line, removed "quiet splash" and added "earlyprintk=efi" but I see no diagnostic information.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[jhoechtl (johann-hoechtl)]

Behavior was caused by buggy Lenovo UEFI Version 2.2 which attempted to verify the Kernel signature even though Secure Boot was disabled.

Closing.

[Bog (tothbog)]

So what is the solution if I own a Lenovo Yoga 720 13? Could you help me out? I have the same problem.

Thanks.

[jhoechtl (johann-hoechtl)]

Actually a later version of UEFI solved the problem again - I am currently running 2.37 and kernel boots properly with secure boot disabled.

However, even after intense web research I didn't find a way to update the UEFI without Windows. So in case you have no Windows any more you have to download a Windows trial image and create a Windows start DVD just for UEFI/BIOS updates.