I tried to install new version of linux-5.5.6-195 on my SLES 15sp1, which current kernel version is linux-4.12.14-195. The kernel package is from https://www.kernel.org/.

The source package is in path /usr/src/linux-5.5.6, and I built new kernel image with below commands.
Code:
# cd /usr/src/linux-5.5.6
# make menuconfig
# make
# make modules_install
# make install
# make headers_install
# rm /usr/src/linux
# ln -s /usr/src/linux-5.5.6 /usr/src/linux

# cd /boot
# rm /boot/initrd
# ln -s initrd-5.5.6-195-default initrd
# rm /boot/vmlinuz
# ln -s vmlinuz-5.5.6-195-default vmlinuz
After that, the system could not be up with new kernel due of invalid signature of ramdisk. Could you please advise on how to handle it?

Thanks in advance.

Best Regards
James