http://wccftech.com/nintendo-switch-4-0-1-firmware/

Following last week’s Nintendo Switch ( Amazon, $299.99) new firmware update, the Japanese company has released a few hours ago yet another update which introduces a fix for a specific issue some users have been experiencing.

The Nintendo Switch 4.0.1 firmware update introduces a fix for HDMI video and audio issues some players have been experiencing since the release of the 4.0.0 firmware. The update also includes other unnamed system stability improvements.