this is from the mobi pocket forums
1) Log into your ebookbase account on
https://www.mobipocket.com/ebookbase
2) Click on "Browse all ebooks" link or use the search box to find the title you want to update.
3) In the result list, click on the title you want to update.
4) You will be redirected to the book details page where you can edit your book information.
5) You can also update your ebook file and/or your cover file.
6) Click on "Save and close book information" on the bottom of the page.