what is the right way to downgrade kernel

Solution 1:

I still cannot find packages of linux-image 3.2 by apt-cache search linux-images*. Where I am wrong?

On spelling. The correct command is

apt-cache policy linux-image-*

Also, the Tab Completion feature is very handy and you should learn to use it. Open a terminal and write

 sudo apt-get install linux-image- 

Then hit Tab key twice and read the list, can you see 3.2 kernel ?

do I need to install linux-header package too, are there more package I should install?

Every linux-image has its own linux-headers version, so it is preferable to install them too.

sudo apt-get install linux-headers- 

and use the same Tab Completion feature (as in linux-image- above) to locate the appropriate ones.