You were unlucky
When use YEM, it always format before install.
If have 5 pacs, and add 1 one without mark the other, only the new pack is in expansionfolder after install.
All have to be marked, and then everything will install in one go.
I've tried all possible ways by use of YEM, same result, it clean up flash memory before install.
Too time consuming procedure...... but as long as I have fresh cofee .......