title: How to create do_populate_sysroot_append task in yocto
body: <p>How could we add some additional kernel files to sysroot directory? I want to extend <code>do_populate_sysroot</code> task, how can we  to copy few more files into sysroot after <code>do_populate_sysroot</code> and before <code>do_package</code>? I tried to create <code>do_populate_sysroot_append()</code> in recipe  but it is getting parsing error. How could we add file in sysroot after <code>populate_sysroot</code> and before <code>do_package</code> task starts? How can we create new task in between?</p>