Here are the instructions from DX58SO2 manual:
Updating the BIOS Using the F7 Function KeyThe .BIO file could be found in Intel's download center. Either download the "Recovery BIOS Update" file or the "Iflash BIOS Update / Integrator Toolkit BIOS Files" bundle. The .BIO file inside the zip archive of the bundle is the same.
To use this BIOS update method:
- Download and save the Recovery BIOS (.BIO) file to a temporary directory.
- Copy the .BIO to a USB thumb drive.
- Plug the thumb drive into a USB port of the target computer.
- Shut down the target computer.
- Enable the F7 prompt display:
- Power the computer on.
- Enter the BIOS Setup by pressing F2 during boot.
- Go to the Advanced > Boot Configuration menu.
- Enable Display F7 to Update BIOS
- Press F10 to save and exit.
- During boot, when the F7 prompt is displayed, press F7 to enter the BIOS Flash Update tool.
- Select the USB thumb drive and press Enter.
- Select the .BIO file and press Enter
- Confirm you want to update the BIOS by pressing Enter.
- Wait 2-5 minutes for the update to complete.
- Remove the thumb drive.
- Restart the computer.