Mecool BB2 reinstall question

Hi folks.

Maybe you can help me out as i can’t find info on here or maybe I have missed it.
I have flashed gxm_q201_2g on my MECOOL BB2 on internal storage but wired network connection is not working. I noticed that there is a different DTB with support or fix for that, gxm_q201_2g_1gbit I believe.

I was wondering how would I go about installing Coreelec again with the correct DTB.img.
Will it auto boot from USB when inserted or from internal storage? What’s the boot order? And how could i tell where it booted from?