I don't think a firmware patch can make the top and bottom headers (much) larger.
However, you could expand the page margins in every epub/kepub manually:
Code:
@page {
margin-top:10pt;
margin-bottom:10pt;
}
Use your own values, this will add the desired space/empty lines at the top and bottom of the screen.
Edit: sorry, I just read that davidfor mentioned it in his previous post.