Given that 64bit UEFI is there, it means that 64bit kernel can run, despite using 32bit userspace otherwise.
Why are you using inferior 32bit kernel, with otherwise 32bit userspace? Please install and use 64bit kernel in such cases, i.e. sudo dpkg --add-architecture amd64 sudo apt-get update sudo apt-get install linux-generic:amd64 "works fine" is not true at all, lots of low-level things in Userspace and kernel are broken when one tries to force booting incompatible kernel due to different memory layout expectations. If you really want to fix it, it will need to go upstream to linux kernel to implement 64bit UEFI memory layouts in the 32bit kernel flavour. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1876737 Title: GRUB refuses to boot a 32-bit kernel when in EFI mode To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1876737/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs