Odroid C2 - No autoboot without serial

[? Yuu?]

Hi,

I have successfully built u-boot for my odroid-c2 on tag v2022.01 and I can see my SBC booting over serial console : yay !

When the serial console is not attached, it does not autoboot, I've just go this message : "Hit any key to stop autoboot :  0" and then immediately the U-Boot prompt. I can see that  just by plugging the "RX" serial cable or over HDMI.

But if I add the all the UART cables (TX, RX, GND) : I can see the "Hit any key to stop autoboot" starting from "2, 1, 0".. and then the boot process continue, kernel is loaded.

After a successful boot, serial is not required anymore, I can even reboot without issues. Instead if I unplung the power to the board, serial is required to autoboot.

Here is my question : how to get the Odroid-C2 to automagically boot without any cables ? (hdmi, keyboard, serial, just the power).
Is there and autoboot setting that I did not got ?

Sorry for my english, it's not my native language : I hope that is understandable :)

Thank you and have a nice day,
Yuu