First of all please make sure that you have verified the md5 sum after downloading the ISO image. If it match the md5 sum which is available on our webpage then please try to reboot your server and upload the newest ISO image once again. No configuration is deleted after the update.

If the update still fails for you unplug the bootable medium and prepare it from scratch with the latest DSS V6 build. After it's booted you just need to set up the NIC address to be able to reach the webgui and then you can restore the setup and configuration from DSS V6 webgui -> MAINTENANCE -> miscellaneous -> Restore settings.

BR,
Tomek