A question about Android recovery disk image and partitions
fastboot boot does not perform a flash.  From fastboot help:

usage: fastboot [ &lt;option&gt; ] &lt;command&gt;

commands:
  [...]
  flash &lt;partition&gt; [ &lt;filename&gt; ]             Write a file to a flash partition.
  [...]
  boot &lt;kernel&gt; [ &lt;ramdisk&gt; [ &lt;second&gt; ] ]     Download and boot kernel.



  Does the recovery image also have its own kernel and ramdisk?


Yup.  Recovery is essentially a miniature OS and boots similarly to the main boot image.