Only if your receiver dont go in recovery mode

For rescue DM900 use usb cable and putty (serial port).

Start receiver and push ctrl+C to enter in cfe mode. Use usb stick for rescue file downloaded from internet.
ifconfig eth0 -auto
show devices
dir usbdisk0
boot usbdisk0:zImage-rescue-xxxxx

Then your receiver get in rescue mode and you can flash firmware.