Devices:

• Sony Bravia KDL-42EX440 LCD TV
• Raspberry Pi 4 Model B (2GB)
  • OS: Raspberry Pi OS (Raspbian) 11 bullseye

Problem:

When connecting Pi 4 to TV via Micro-HDMI to HDMI, the boot-loader and initial splash shows up. As soon as the desktop loads, the TV shows no signal.

Solution:

Raspberry Pi OS (Raspbian) 11 uses KMS driver by default, which is not compatable with this TV model. We need to switch to FKMS drivers.

1. Find a way to access your system file in Pi (either via SSH, use secondary PC monitor, or plug your Pi's SDcard to a working PC and access the partition where /boot is located)
2. Edit config.txt in your /boot system folder as a super user. Ex: $ sudo nano /boot/config.txt
3. Find the line dtoverlay=vc4-kms-v3d, change it to dtoverlay=vc4-fkms-v3d. Uncomment if it is commented out, add if line doesn't exist.
4. Connect your Pi's HDMI to TV, turn both on.