Bios Trouble with ASUS EAH5870V2

[Cr@zed^]

First of all, sorry for my bad English.

After I installed yesterday the ATI DD 10.5 I reconized my 2D Clocks were set to 400/1200,
so I decided to delete the 10.5 and reinstall the 10.4.
All works fine till I tried to OC my Card to 900/1250 again. Before I had no Troubles with this.
When I set now the clockrates to 900/1250 and click the accept Button my Sys freezed immediately mostly with an Orange Black striped Screen.
After this I extrect the Bios with RBE and changed the clockspeed by Hand in the Bios. I tried to flash the Bios with RBE and Winflash, but it didn't work.
Then I tried to flash the Bios just with Winflash and get following Errormessage:
"Winflash can not delete Rom"

Why I can't flash the Bios?

So my next try out was the Smart Doctor Software. I set the clockrates to 900/1250 and guess what. Clockrates can be changed ....
But I don't want to run this crappy Asus Software ...

Someone know what I can try out now?

OK update:

Flash the Bios worked with ATI Flash, first I had to unlock the Rom

X:/ ATIFLASH -unlockrom
X:/ ATIFLASH -p -f 0 biosfile.bin worked

Now I got my 900/1250 @ 3D and 157/300 @ 2D, but if I enable Overdrice I still get 400/1250