Zero3 3w doe'nt boot form eMMC after flashing with RKDevl 2.96Tool V1.26

Have two zero 3w (2GB,16GB eMMC, 4GB, 32GB eMMC) on neither of them I get the offical images running. I followed the procedures descirbed in the documentation with RKDevTool V2.96.
The boards don’t boot form eMMC although flashing finishes allways with ok.
Running the boards from sd card doesn’t work either. There some Armian images run to the root console and that’s it.
I have a bunch of rock pi 4c everythings working fine.

Where is my mistake? Can’t see it at the moment.
Thanks for any help

How do you power the board? which os do you use, Can you take a video about your steps, and can you catch the serial log and paste it here?