Hello Igor,
First, Thank You for all great work over Armbian !
I tried about all previous releases and they started over HDMI port normally with factory U-Boot 2013 ... Now Armbian 5.00 I tried all posted release Legacy and Vanilla Kernels and only Jessie Desktop show startup process and show GUI screen.
Igor, may You help Me Please, How to upgrade factory board U-Boot with Your U-Boot version ?