said, if there's nothing wrong or reason to update, don't do it.
Still, if you must, here's the page for your BIOS and Manual
. Download the manual in the language you prefer and the BIOS version. The newest version looks to be 1406.
Open the manual pdf, updating the BIOS instructions start on page 54 (section 2-2). Carefully read over each method and choose the one right for you. The EZ Flash 2 Utility on page 60 (section 2-8) looks simplest.