If the device is bricked then follow Post #6 in detail. If it's not bricked then first ensure that it's in Mass Storage Mode because you cannot attain preboot in Media Transport Protocol: [Only registered and activated users can see links. ].
If preboot is totally unattainable it may be possible to still flash it using SD card text commands and BIN files. Additonally to the info in your other post [Only registered and activated users can see links. ], tell us precisely in fine detail what all your previously actions were and provide links or attachments to files/firmware you've used in manipulations. It's particularly important you supply the the dezl 580 firmware used.