Rockpi4a doesn't boot and no serial output

Hi folks,
I got two rockpi4a nodes with eMMC (as boot drive) and an m.2 SSD - I successfully managed to set one up by flashing the eMMC with the ubuntu image, however the second one doesn’t boot at all - I tried eMMC and sdcard with the ubuntu image and neither one was successful. I tried removing m.2 drive, eMMC card from it with no change. I also get no output via HDMI in any case.
Now I got a TTL serial adapter and other than an initial output of “ÿð” I get no further data from the rockpi.
Is this DoA or am I doing something wrong?

Is the LED on? What power adapter are you using?