Update faq.md

pages/faq.md

@@ -110,6 +110,19 @@ As a first step we recommend carefully reading our documentation on [GitHub](htt
 * Details [here](https://github.com/pikvm/pikvm/issues/6). The reason is that the [official HAT](https://www.raspberrypi.org/products/poe-hat) has a built-in fan controller that conflicts with the TC358743 chip of the bridge. The solution is to disable the fan control and connect it to the power line so that it works continuously. To turn off the controller you need to add the line `disable_poe_fan=1` to `/boot/config.txt`.
 </details>
 
+<details>
+  <summary><b>The video freezes a few seconds after the start, restarting the Web UI or VNC does not help</b></summary>
+
+* The story is [here](https://github.com/raspberrypi/firmware/issues/1562). Very-very rarely, Raspberry boards can have a hardware defect that causes some of the chip blocks to be unstable under normal power. The solution is to slightly increase the power supply, as in overclocking. Add `over_voltage=1` (or `over_voltage=2` if previous doesn't help) to `/boot/config.txt` and perform `reboot`.
+
+  To make sure that you are facing this particular problem, first perform a diagnostic:
+  - Boot the Pi-KVM without the specified options.
+  - Open Web-UI and wait for freezing.
+  - Click **System -> Reset Stream**.
+  - Click **System -> Open log** and make sure that the log contains messages like `H264: Can't wait for the VCOS semaphore`.
+  - Make sure that the last message from ustreamer was `H264: Configuring MMAL encoder` (not counting messages about connecting and disconnecting stream clients).
+</details>
+
 <details>
   <summary><b>No image from computer with Linux + Awesome WM</b></summary>