Troubleshooting • Re: Pi 5s will not boot from SD.

posted this a number of times:

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The latest "bullseye" and "Bookworm" and "Trixie" releases use the KMS video driver.
The KMS driver seems less forgiving when the EDID data from the monitor is bad, nonexistant, or malformed.

If you get no display:
probably, your PI OS cannot figure out the EDID data from the monitor, and as such, cannot figure out what resolution to set.
unfortunately, this results in the PI setting none... no display
there have been many reports of "failed video output" which boil down to bad or non-existant EDID data from the monitor. This is an issue more often with the new KMS driver in Bullseye, Bookworm and trixie.

note: many HDMI adapters do not pass data in both directions, and can be the cause of no EDID Data. It is recommended to get the proper cable, and not use adapters.

another note: the KMS driver ignores all video settings in config.txt - video mode changes made to this file will have no effect !
(see this: https://www.raspberrypi.com/documentati ... splay-mode)

NOTE: this assumes an updated Bootloader (PI4/400/5). if you are not sure, update it... instructions here:
https://www.raspberrypi.com/documentati ... ate_stable

- check your HDMI cabling and EDID status:
power off your PI
remove the SD card
power on the pi.
- you should get the diagnostic display as shown below. Pay attention to the EDID data status (the last line "display"... below says EDID=OK)
if you do not get the diagnostic display, it may be your cabling or an adapter? - check your cabling

however, you can set the resolution manually: (below location is for current PI-OS, Trixie)
in /boot/firmware/cmdline.txt (add to the front/end of the line, NOT a new line)
video=HDMI-A-1:1024x768@60D
(or whatever resolution you want)

Statistics: Posted by terribleted — Wed Dec 24, 2025 2:49 pm

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