How to disable logo

How to disable the trixbox logo that appears on the phones?

If that is what you are asking - you can easily make your own, or if you want it blank (not sure why you wouldnt use that space for something) - but just edit the files located in
/tftpboot/polycom/bmp

they are standard (but small) windows bitmap files - you can easily blank them out or change them with any decent photo editor....