well if you say it is bricked then it is bricked.... otherwise if it is just a black screen because his update cd was crap then it probably can be saved with a proper update cd once you have opened the unit and released the crap cd...
I don't know where you found it, but if it is a nero image (.nrg) you should write it with nero and it should be fine, if it is iso then you should write it with magiciso in MODE2, but the best would be to get a ccd+img+sub format image and to write it with IMGburn, alternatively you can order a factory update cd for as low as 5 eur from tomtom (teleatlas)
I had the same problem not reading all the threads. I burnt the NRG file using imageburn then put the disc into the PC5400 and ended up with a black screen, the disc would not eject. i had to remove the unit from the car open it up to remove the disc. i put the unit back into the car burnt a new disc using nero.
when the unit was back in the car i found i could not insert the new disc, out come the unit again pulled it apart insert then new disc. install the unit for the second time, power it up and it automatically installed the new SW 980. Unit is working fine.
what i suggest when installing the new disc into the unit place paper under the disc so you dont scratch it and when in place just remove the paper put it all back together and it should be all good.