Raspberry pi 4b, no hdmi display, no network (solved, power supply issue)

I have a raspberry PI 4b, with an case that came with the system.

I am trying to boot with the hdmi screen, and usb keyboard, plugged into a switch. The screen turn on when the rpi boots, but within 5 seconds the monitor reports no signal.

I have changes some settings in the SD card boot partition, confit.txt:



nothing appears to work, same problem.

The ethernet interface does not appear to be enabled either, nmap does not find the host (other than my desktop & the adsl modem/switch)

The system boots fine with an ubuntu image.

I have also tried to check log files (/var/log/*) in the rootfs partition of the sd card. but there doesnt appear to be anything relevant there (no kern.log?).

Any help appreciated

Edit: This was a power supply issue.