Comment # 12 on bug 1008737 from Freek de Kruijf

(In reply to Michael Chang from comment #11)
> @Freek,
> 
> Could you please test reverting the save_entry settings that YaST did for
> you and retest with $default with unset value, to know it really cause of
> problem ?
> 
>  # grub2-editenv /boot/grub2/grubenv unset saved_entry
>  # reboot

I did the above, the system came back with the same kernel, the highest
available, 4.4.27-1.1.
After that I did "zypper up kernel-default" which installed 4.4.27-2.1.
I did a reboot, the grub screen did not show the new kernel and now I am still
using the 4.4.27-1.1 kernel.
I did the following:
eik422:~ # ls -l /boot
totaal 54400
-rw-r--r-- 1 root root      512  5 nov 13:37 backup_mbr
-rw-r--r-- 1 root root     1725  7 okt 17:50 boot.readme
-rw-r--r-- 1 root root   178496 28 okt 13:29 config-4.4.27-1-default
-rw-r--r-- 1 root root   178496  5 nov 00:16 config-4.4.27-2-default
drwxr-xr-x 7 root root     4096 14 nov 11:17 grub2
lrwxrwxrwx 1 root root       23 14 nov 11:12 initrd -> initrd-4.4.27-2-default
-rw-r--r-- 1 root root 11117208  5 nov 12:28 initrd-4.4.27-1-default
-rw-r--r-- 1 root root 11117100 14 nov 11:12 initrd-4.4.27-2-default
-rw-r--r-- 1 root root   500736 19 okt 22:29 message
-rw-r--r-- 1 root root   355901 28 okt 14:15 symvers-4.4.27-1-default.gz
-rw-r--r-- 1 root root   355901  5 nov 00:44 symvers-4.4.27-2-default.gz
-rw-r--r-- 1 root root      377 28 okt 14:15 sysctl.conf-4.4.27-1-default
-rw-r--r-- 1 root root      377  5 nov 00:44 sysctl.conf-4.4.27-2-default
-rw-r--r-- 1 root root  3184412 28 okt 13:56 System.map-4.4.27-1-default
-rw-r--r-- 1 root root  3184412  5 nov 00:40 System.map-4.4.27-2-default
-rw-r--r-- 1 root root  6864874 28 okt 14:19 vmlinux-4.4.27-1-default.gz
-rw-r--r-- 1 root root  6864663  5 nov 00:50 vmlinux-4.4.27-2-default.gz
lrwxrwxrwx 1 root root       24 14 nov 11:12 vmlinuz ->
vmlinuz-4.4.27-2-default
-rw-r--r-- 1 root root  5874568 28 okt 14:57 vmlinuz-4.4.27-1-default
-rw-r--r-- 1 root root       65 28 okt 14:57 .vmlinuz-4.4.27-1-default.hmac
-rw-r--r-- 1 root root  5874344  5 nov 01:30 vmlinuz-4.4.27-2-default
-rw-r--r-- 1 root root       65  5 nov 01:30 .vmlinuz-4.4.27-2-default.hmac
eik422:~ #

As you can see /boot/initrd and /boot/vmlinuz point to the new kernel, but
apparently grub does not use these names to boot this system. Apparently I have
to use YaST bootloader or the underlying command line utility to make grub
aware of the new kernel.