Version for `uname -r` remains despite successful rpi-update

Question

I did install my Raspberry PI using debian-pi/raspbian-ua-netinst like described in this SO Post

Now uname -r returned

3.18.0-trunk-rpi

When I ran rpi-update it seemed to have successfully installed the two upgrade packages (I don't know why there are two):

*** Backing up modules 3.18.0-trunk-rpi
#############################################################
 This update bumps to rpi-4.1.y linux tree
 Be aware there could be compatibility issues with some drivers
 Discussion here:
 https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=113753
##############################################################

So ls /lib/modules/ now returns three modules:

3.18.0-trunk-rpi
4.1.6+  
4.1.6-v7+

When I now run rpi-update it tells me that the system is up to date:

 *** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom  
 *** Performing self-update  
 *** Relaunching after update  
 *** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom  
 *** Your firmware is already up to date  

However, after a reboot, uname -r still shows 3.18.0-trunk-rpi rather than one of the newly installed upgrades.

I wonder how I can now update my PI to the latest firmware.

Answer 1

If you look at /boot you should have 4055296 Aug 30 15:47 kernel.img (the date will of course differ, depending when you updated). The earlier kernel was 3974884.

rpi-update was notorious for installation problems. I don't know how it is now, but I haven't used it for years. You should use apt-get update and apt-get upgrade to install the latest.

Answer 2

The kernel to load is specified in /boot/config.txt. The rpi-update script should have created a kernel.img file in /boot/ but the config.txt file is still pointing at the old kernel. By default, the Raspberry Pi will boot the file named kernel.img if you don't specify an alternative. More information about config.txt can be found on the official site.

To fix this, simply look in /boot/config.txt for a line starting with kernel= and comment it out by putting a # at the start, then reboot the Pi to load the new kernel named kernel.img.

You can do this from the command line with the commands:

sudo sed -i 's/^kernel=/#kernel=/' /boot/config.txt
sudo reboot