Display Morejunger is correct as certain dm800 receivers have this reset button on the back which would be a godsend..
If all else fails try this below as i can confirm this does sort bootloader/corrupted image issues...however you will need a comp with a serial port.
http://linuxsat-support.com/showthread.php?t=35300&p=133627&viewfull=1#post133627
MK
hi Mee®kat
Your link i load it.
But it dosn't work and it get this small usb port on the back