Hello Akira357,
The information in About firmware updates for AirPods provides some insight into how firmware updates work for your AirPods.
"Firmware updates are delivered periodically while your AirPods are charging and in Bluetooth range of your iPhone, iPad, or Mac."
You mentioned that you're hearing cracking and static sounds from the AirPods. If you have the 1st generation AirPods Pro, If your AirPods Pro (1st generation) make crackling or static sounds provides some specific steps for your issue.
- "Make sure that you have the latest software on your connected iPhone, iPad, iPod touch, or Mac.
- Check that your connected device is nearby, and there's no wireless interference or obstructions between you and your device.
- Listen to audio from a different app to see if the app causes the issue.
If you still experience sound quality issues—or if the issues increase in loud environments, with exercise, or while talking on the phone—refer to AirPods Pro Service Program for Sound Issues."
If needed, here's how to confirm which model AirPods you have: Identify your AirPods
Take care!