Does aTV Flash (xbmc edition) wipe the internal drive during install?

Currently running an ATV1 with the old aTV Flash (silver). Would love to upgrade but want to know if I need to know if the install deletes everything, and if I should backup and reinstall all the media as part of the install? Clearly I would prefer to avoid a massive file transfer

http://firecore.com/atvflash-xbmc

As it says powered by Openelec so yes it will