own cape - booting problem


I build an own cap with relays.
Now I have on “gpio10” (P8_31) an devicetree overlay with direction out.

When the BBB are booting, I have on this pin 2.78V … after some seconds, he load my device tree(?) and all outputs are for 1 sec on and then off. After this, “gpio10” has 0V and it is output.

So my question:
How can I set the devicetree for GPIO at boot time? When “gpio10” is connected to my relay, the LED of my relay are glimming and the BBB doesn´t boot.

Or can I disable all gpio at boot time and enable it after he load my devicetree?

Thank you!

As far I found in the web, I have to rebuild u-boot to have my gpio settings at boot time?

If yes, can someone help me to build this?

Thank you!

Hello Again!

Just want to ask again, if someone has a link or can help me, to set my DeviceTree at Bootstart.

Right now with uEnv.txt he load the DeviceTree after booting.

Thanks a lot!