Nemavio

Hello,
Thank you for your answer.
For a reason I don't get, but I had to strap Jumper P10 and P11, and I got something on the serial line.
 
https://wiki.kobol.io/helios64/jumper/

 
The bootloader appears and linux starts after 2-3 minutes.
 
We can say that it is solved but I don't understand why.

Hello,
I received recently an Helios64 from a new friend,
However, when I get home, I plug it in, turn it on (already I have to press the power button for 4 seconds to get some life) and I get the following LEDs lit up:
- LED1
- LED2
- LED3
- LED5
- LED6
i got nothing on the serial line (tested on MacOS and Windows), and no reaction when I do quick and long press on Recovery nor Reset.
 
Is there some electronic schematic that could help me to debug hardware or procedure to get JTAG access to the RK3399 ?
 
Regards,