If you are already able to access a utility to flash the chip you shouldn't need FlashBIOS... all that this does is provide the ability to flash the chip. (Ok, it does HDD lock/unlock too.) You say only a black screen after flashing, is there any sound? If so this is often the sign that the wrong BIOS version was flashed for the mobo. (1.6 mobo with vOld BIOS, 1.0 to 1.5 mobo with 16plus BIOS) Are you sure that this is a 1.6 Xbox, or that you have the 1.6 BIOS file? I wouldn't trust a download from IRC, torrent, unknown FTP site or web page. Use xbins, it should be the only download site you'll need.
BTW, FlashBIOS is downloadable right from the Team Xecuter site. Go to the front page and look at the downloads section. There are two current versions (read the download pages to see why) v3.0.1 and v3.0.3. You may need to right click and "save as" to get the actual BIOS files downloaded.
-Whoopin'