The mars-buildroot-sdk does not fully boot to a login promed on the mars not mars-cm

So I got my mars the other day and so far I’m pleased but I’ve run into a few problems. I was able to get the debian image to boot and it works great but it’s way over-kill for my needs and I wish to make my own debian image. I’m trying to play with the buildroot-sdk but it does not work. I successfully build and got an sdcard image following the instructions on git hub. It took awhile to build everything. I put it on a sdcard and it almost boots but hangs up after doing something with urandom. I can’t open a tty and I can’t get a login prompt. I’m also wondering how I can use the u-boot.bin to build my own image, so any explanation on how u-boot works to boot the mars.

It tuns out it does boot all the way. You can get a prompt when connected by uart.