How to install newer kernel

I’d like to install the latest kernel from in order to test some hardware compatibility.

From what I’ve found online the two options are basically just to specify the kernel version during install:

zypper in kernel-default-4.20....


zypper dup --from kernel....

The first option results in a “must first load kernel” error (or something very similar to that) after selecting the kernel from the grub boot menu.
The second option requests that I uninstall the current kernel with the vendor change to the new repository. I’d like to avoid uninstalling the current kernel. I have multiple kernel versions enabled in the zypp.conf file.

So, my question is, how do I install the new kernel alongside the current Leap 15 kernel while also getting it to boot from grub? Do I just need to update grub somehow, and if so, how should I go about it.? I’m using UEFI boot with multiple hard drives, if that makes any difference.


Update: It doesn’t matter which method I use to install a newer kernel, both result in

error: you must load the kernel first

when attempting to boot.

I replied in the other thread on what I did to add 4.20.x from the kernel:stable repository…

Disable secure-boot in your UEFI firmware (or BIOS).

The kernel that you just installed is signed by a different key, and not recognized by your boot setup. There are other ways around this, but disabling secure-boot is the easiest and quickest.