|Did you get the 'checksum' error before the BIOS flash, or only after the attempt? It does matter!!! If you were getting it before, then the flash you made was for the purpose of trying to fix a problem and this attempt probably did not help (or you would not be asking). If the error only happened after you tried to flash your BIOS, then you caused the error, possibly by using the wrong update (the correct update in extremely important).|
Look at this article:
And you might also get something out of reading this also:
You have to be a little bit crazy to keep you from going insane.
If all else fails, read instructions.