the new BIOS will probably use more ROM than the previous version. The difference in the BIOS image file byte count is detected by the system as a checksum error.
Enter the BIOS by pressing the delete key as the computer boots. Once in the BIOS configuration dialogue, go through the various settings, but DON'T CHANGE ANYTHING.
Then, save and exit. This will cause the BIOS to generate a new checksum and write it to the CMOS. Shut down the computer and restart. With luck the system will generate a checksum, compare it with the one that was written to the CMOS and find them the same.
There's no guarantee, but try it.
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