You can change the boot picture to anything u want mate, you can download preprepared images or create your own from any picture u like, there are tools that make it a simple process.
The boot image is called logo-fb, here is a site with a few ready made images, the site also has the tools to allow u to create your own.
How do I do this on a Dreambox using the latest DW flash would be nice to have a custom logo when it boots. Which files would I need to change and what format.