This update is for the Steam Deck Beta and Preview channels, and includes new features that are still being tested. You can opt into this in Settings > System > System Update Channel.
Note: This beta contains changes that were simultaneously released to SteamOS stable channel as 3.8.13, noted below
General
The Steam Machine splash screen/logo now appears much more quickly after device startup
Add option to reset all audio configuration and settings to system defaults under Settings -> Audio
Fixed 20-30s startup delay in some games on non-Valve devices with no audio sources
Fixed a regression with some MSI Claw devices on newer firmware losing access the Guide and Quick Access Menu buttons.
Fixed a regression with Legion Go 1 models on older controller firmware where gyroscope would fail to initialize.
Fixed a regression on OneXPlayer F1 models where rumble was being blocked and the joystick poll rate was low. As a consequence, the M1 (left) extra shoulder button is no longer able to function.
Added controller support for missing OneXPlayer F1 and OneXPlayer 2 special edition models.
Fixed in 3.8.13