...so far I see,your method seems to me that working...!...
but what if I have ATI card?
My gpu is ATi Mobility Radeon 9600/9700,with id 4e50(M10/M11),vendor id1002...,on notebook Clevo TurboX D870!
So,what I did:
I want just to modify the clocks of gpu & memory(to decrease)-by the bios was 486MHz/520MHz DDR,and I extract the bios file with AtiFlash program,I just decrease the clocks(nothing else),I save the bin file modified,and I flash the vbios with the same program!
My mistake,of corse,was that I flashed from windows...!....so,start flashing,after give me a messege that can't erase rom,I click "ok" then "erasing rom"...I wait 2 hours,but nothing happened...still this message "erasing rom"...!
...I restart my PC,and...Black screen!
Now,I've tried "blind flash"with "flashrom" and "atiflash"programs...!
I create USB bootdisk,I create CD bootdisk with another flash file found on only "techpowerup.com"site-the flash file is not original,is not for mobile,but the clocks are allmost the same(because the original bios file is on the 2HDD's of the notebook,are configured in RAID mode,so I can't explore them to take the original flash file),...I create autoexec.bat file with the commands required by the flash programs,I insert the command" -f" to force flashing...but nothing happened...-I think that I did anything possible...!
Now,the pc ,I think, boot from USB flash drive,because when I power on the pc the LED start flashing few times then stay ON few minutes,then the LED goes OFF and nothing happened!
PLEASE,if you have any suggestion I'll appreciate a lot!
Thanks in advance!