The simplest way is to extract the BIOS from you own video card. You can do this with a flashing utility, for example:
flashrom -s 0 my_bios.rom
You can also use a BIOS image from a compatible video card from the Downloads section of radeon2.ru.
You may do that for changing PAL/NTSC TV standard, or for better overclocking. For example, flashing a retail Radeon 8500 BIOS to a OEM/LE card can give you 2-5 Mhz or even more memory overclocking potential.