Thanks a lot for helping me out here. I have managed to solve it, or at least found a workaround.
The system uses u-boot, and picks uImage and uInitrd from an external sd card at boot time. When I ran flash-kernel tool manually I saw that new uImage and uInitrd files were generated, but not in /boot. It says "using /dev/sda1 as boot device", but that is and internal sd card, not used. /boot is on /dev/sdb1, so I simply mounted /dev/sda1 and copied the generated files to /boot, and after reboot the correct kernel is running. I am not sure this is the proper way to do it, but it works now. This was the output before copying the new files: # flash-kernel Installing kirkwood-dreamplug.dtb into /boot/dtb-3.16.0-4-kirkwood Taking backup of dtb-3.16.0-4-kirkwood. Installing new dtb-3.16.0-4-kirkwood. flash-kernel: installing version 3.16.0-4-kirkwood Generating kernel u-boot image... done. Will use /dev/sda1 as boot device. Taking backup of uImage. Installing new uImage. Generating initramfs u-boot image... done. Taking backup of uInitrd. Installing new uInitrd. Taking backup of dtb. Installing new dtb. # ls -l /boot total 25406 -rw-r--r-- 1 root root 135743 Jan 18 02:38 config-3.16.0-4-kirkwood lrwxrwxrwx 1 root root 21 Feb 15 23:38 dtb -> dtb-3.16.0-4-kirkwood -rw-r--r-- 1 root root 10037 Feb 15 23:38 dtb-3.16.0-4-kirkwood -rw-r--r-- 1 root root 10037 Feb 15 23:05 dtb-3.16.0-4-kirkwood.bak lrwxrwxrwx 1 root root 28 Jul 24 2015 initrd.img -> initrd.img-3.16.0-4-kirkwood -rw-r--r-- 1 root root 10006903 Feb 14 23:51 initrd.img-3.16.0-4-kirkwood drwx------ 2 root root 12288 Jul 24 2015 lost+found -rw-r--r-- 1 root root 1621549 Jan 18 02:38 System.map-3.16.0-4-kirkwood -rw-r--r-- 1 root root 2081989 Jul 25 2015 uImage -rw-r--r-- 1 root root 9950850 Jul 25 2015 uInitrd lrwxrwxrwx 1 root root 25 Jul 24 2015 vmlinuz -> vmlinuz-3.16.0-4-kirkwood -rw-r--r-- 1 root root 2074112 Jan 18 02:37 vmlinuz-3.16.0-4-kirkwood BR -Martin Den 2016-02-15 kl. 14:07, skrev Uwe Kleine-König: > Hallo, > > On 02/15/2016 01:29 PM, Martin Granehäll wrote: > ... > > _Kernel policy:_ > > linux-image-3.16.0-4-kirkwood: > > Installed: 3.16.7-ckt20-1+deb8u3 > > Candidate: 3.16.7-ckt20-1+deb8u3 > > Version table: > > *** 3.16.7-ckt20-1+deb8u3 0 > > 500 http://security.debian.org/ jessie/updates/main > > So you have a newer kernel installed than you are running. You might > want to check your bootloader settings. > > Best regards > Uwe
