Say it is lat at night… and you got some issues and without thinking you do a "sudo rpi-update" with the EMLID kernel for NAVIO installed… oppsss you end up on a standard kernel without the pwm fixes etc. And can no longer run the ArduPlane/Coptr etc. code… And say you had done a loot of things with this image and really do not want to start over…
Well I did this… And found no official way to downgrade me back…
So this is what I did:
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At some time BEFORE you do anything, make a copy of the /boot and all sub catalogs, then you may simply copy this back to /boot and reboot…
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It’s to late you did not do this, then make a new EMLID image on a empty uSD card, and copy this over. I found it easiest to:
Boot the raspberry pi with the new image,
connect to local net with you’re computer,
make a backup catalog on you’re Windows/Mac/Linux computer,
and then use the “scp -r pi@192.168.1.12:/boot .” this will copy the boot files to you’re computer.
Now reinsert the bad card and boot the Raspberry,
then use “scp -r . pi@192.168.1.12:/boot” top copy the files back from you’re computer to the broken card.
Then do a “sudo reboot” in ssh, or simply repower…
And volaaa you are back to the EMLID kernel…
Definitely a hack, but also will save you a loot of frustrations !!!