I'm booting a pogoplug mobile from a USB flash drive, and I've installed uboot-pogoplugv4 2015.10-1 and linux-kirkwood-dt 4.3.3-1. This works only if I have another computer set up to monitor netconsole output. If there's no computer to accept netconsole output, it never shows up on the LAN. Also, there is no systemd journal for the failed boots. However, the LED on the front does turn green. I didn't have this problem with the non-dt kernel.
So, in other words, if I'm watching uboot and kernel output to try to diagnose the problem, it works fine. If I'm not watching, it fails.