Choose kernel to boot BBB

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1

Hi, I have a BBB rev C.

I installed the latest debian image (2015-03-01, Kernel: 3.8.13-bone70) and flashed it to the eMMC. After that, I followed some instructions to install a Preempt kernel.
The guide I followed is this one: http://dev.ardupilot.com/wiki/building-the-code/building-for-beaglebone-black-on-linux/

Apparently, all went well. I only skipped a step where I had to make a backup of a zImage. And that’s one problem, there’s nothing in /boot/uboot/, I can’t find zImage… Is that normal? I thought that zImage was called at boot time to load everything, so where does my BBB boot from?

But the installation of Preempt looks fine.

root@beaglebone:~# ls /lib/modules
3.8.13-bone70 3.8.13-rt9-00899-g6d55dce-dirty

I have the rt folder, but

root@beaglebone:~# uname -a
Linux beaglebone 3.8.13-bone70 #1 SMP Fri Jan 23 02:15:42 UTC 2015 armv7l GNU/Linux

i’m still running the old kernel version, how can I boot from the Preempt kernel?

Thanks in advance.

2

Make sure you set the uname_r variable in:

/boot/uEnv.txt

uname_r=3.8.13-rt9-00899-g6d55dce-dirty

Then make sure:

/boot/dtbs/$(uname -r)/*.dtb
/boot/vmlinuz-$(uname -r)

exist...

Regards,

3

Thanks for your answer.

I changed that in the uEnv.txt file but now my BBB does not boot. When I power my BBB, the four leds are stationary and they don’t blink as they did before. So maybe, the Preempt kernel is bad installed? or could it be anything else?

4

I’m sorry, I forgot to tell you in my last comment that I don’t have those files:

/boot/dtbs/$(uname -r)/*.dtb
/boot/vmlinuz-$(uname -r)

Maybe the tutorial I followed is not very up to date, It says nothing about those files so I don’t know where to get them.

Thanks

5

yeah, it's an old tutorial..

vmlinuz-$(uname -r) = zImage

and just mkdir -p /boot/dtbs/$(uname -r)/

and copy your newly built *.dtb to it..

/boot/ is on the ext4 partition (rootfs)

Regards,