Unfortunately that is a serious problem. Somehow you have a failed corrupted update. When that happens you have to send the unit to a certified service center to have the BIOS re-flashed. This can only be done at a certified service center. Until then your receiver is bricked as you say. Also in view of the previous problems you noted, there may also be more serious problems the service center will have to identify.
That receiver is three years old, however it is on the lower end of the food chain so to speak. So it is a marginal decision as to replacement versus repair.
If funds are available, putting the funds towards a higher end receiver should be seriously considered. It seems to me there are more issues in the lower priced receivers. This is a difficult decision and it is not possible to give you definitive advice.
May be you should contact the service center and ask what it would cost to flash the BIOS and re-install the firmware. If the unit is still non functional, I think I would instruct the center to recycle the unit.