I've never flashed a Fujitsu PC, however the problem probably won't be solved with a BIOS flash and I can guarantee that you won't be able to boot off the drive with more than ~2.2TB which requires both GPT, 64-bit OS and a supporting UEFI BIOS i.e. N/A on any LGA 775.
What you should see is two partitions 800GB + 2.2TB. Once the drive is mounted choose GPT option if available.
The following is listed (copy/paste) from your manual. I really don't recommend updating your BIOS from Windows the risk is too high that you'll 'brick' (ruin) your MOBO. Also, I realize it lists a FDD (floppy) if you don't have one then you can 'try' making a bootable USB; you'll need to Disable Legacy USB in the BIOS. The 'Linux boot disk' sounds promising as a viable method for a bootable USB. If you post that link I'll try to read the documentation.
When should a BIOS update be carried out?
Fujitsu Siemens Computers makes new BIOS versions available to ensure
compatibility with new operating systems, new software or new hardware. In
addition, new BIOS functions can also be integrated.
A BIOS update should also always be carried out when a problem exists that
cannot be solved with new drivers or new software.
Where can I obtain BIOS updates?
The BIOS updates are available on the Internet at "www.fujitsu-siemens.com/mainboards".
BIOS update under DOS with bootable BIOS
update floppy disk - brief description
► Download the update file from our website to your PC.
► Insert an empty floppy disk (1.44 Mbyte).
► Run the update file (e.g. 2750103.EXE).