the reason it only works with the TV ON prior to boot is that the PI interrogates the TV to see what resolution to set.
if the TV is off, the PI does not know what resolutions the tv is capable of.
in some cases, the PI turns off the display in this case. I've seen that happen a number of times on the forum, where the user is using an adapter (adapters sometimes do not pass data BACK)
So, in order for this to work properly, the TV must be powered BEFORE the PI boots.
Another thing.... the new KMS driver ignores all video settings in config.txt
(see this: https://www.raspberrypi.com/documentati ... splay-mode)
Setting the video resolution in cmdline.txt is the preferred method.
you need to add a "d" to the end of the setting. like this
video=HDMI-A-1:1024x768@60D
have you tried setting the VNC resolution in raspi-config?
or in the VNC viewer itself?
if the TV is off, the PI does not know what resolutions the tv is capable of.
in some cases, the PI turns off the display in this case. I've seen that happen a number of times on the forum, where the user is using an adapter (adapters sometimes do not pass data BACK)
So, in order for this to work properly, the TV must be powered BEFORE the PI boots.
Another thing.... the new KMS driver ignores all video settings in config.txt
(see this: https://www.raspberrypi.com/documentati ... splay-mode)
Setting the video resolution in cmdline.txt is the preferred method.
you need to add a "d" to the end of the setting. like this
video=HDMI-A-1:1024x768@60D
have you tried setting the VNC resolution in raspi-config?
or in the VNC viewer itself?
Statistics: Posted by terribleted — Sun Feb 15, 2026 9:50 pm