SteamdeckHQ reports that the recent 3.5.1 SteamOS update also came with a new BIOS firmware ver 118. Located in the SteamOS preview branch, this new version’s only change appears to be adding undervolting to the BIOS menu. Undervolting was possible before, but it could brick your device if you were too aggressive. To help prevent this, Valve appears to have put in a safety net in the BIOS that should save a lot of Steam Decks. Now, performing a CMOS reset (hold down the Volume Down button, 3 dot button, and power button at the same time) will also reset the undervolt settings to defaults.

Why undervolt your console? If your system is stable, your Steam Deck will typically run cooler, keep the fan quieter, possibly maintain higher speeds longer, and most importantly – improve the battery life.

Article:

• https://steamdeckhq.com/news/steamos-bios-makes-undervolting-safer-easier/