Hey! Sorry by the late reply.
Thank you for all the answers, I'm really new on this, so helped me a lot! I followed all the steps, read the documentation and build a minimal image.
I kept trying to generate an image by Debos, but unfortunately I still not getting the armbianEnv.txt file and also still having problems with serial. Anyway, my initial purpose was generate the image and boot my board, and this happend. I'll keep trying to use Debos, and if I get it, I come back here to share!
Again, thank you for all support!