Is it possible to uninstall the default flash plugin before installing the new version? apt-get remove --purge adobe-flashplayer By using this method you can avoid the diversion of the flashplugin binary and the space occupied in the rootfs dir.
/home/user # apt-get remove --purge adobe-flashplayer Reading package lists... Done Building dependency tree Reading state information... Done The following packages will be REMOVED: adobe-flashplayer* mp-fremantle-generic-pr* 0 upgraded, 0 newly installed, 2 to remove and 4 not upgraded. After this operation, 6795kB disk space will be freed. Do you want to continue [Y/n]?