VNC is a black screen after update - Raspberry Pi Forums
forums.raspberrypi.com › viewtopicFeb 07, 2017 · Re: VNC is a black screen after update. If you don't have a HDMI monitor attached then you MUST set the screen resolution in /boot/config.txt. You can use sudo raspi-config or the GUI config tool to set the resolution that you want to use. Unless specified otherwise my response is based on the latest and fully updated RPi OS Bullseye w/ Desktop OS.