Porting to U-boot driver model and device tree control (for ARM-based design)

I'm attempting to port U-boot - running on an SoC with a Cortex-A9 - to the new(ish) driver model and device tree (fdt) control functionality.  To start with, I tried to keep the device tree limited to what was necessary to launch and get to the command line (IE: I defined CPU, timer, and UART).  Then, I compiled with CONFIG_OF_CONTROL and CONFIG_OF_SEPARATE, and loaded/jumped to u-boot-dtb.bin in memory.  However, nothing prints out on the console so I have no insight into what's wrong.

Previously, all UART and timer config details were set up in the board-specific files (include/configs/<board>.h and board/<vendor>/<board>/<board>.c).  Has anyone done the port from this format to driver model and device tree before, and how did you go about debugging before you got the early low-level details working from the device tree?  Is there an easy way to leave the very early details (at least UART) in their current "hardcoded" format to allow for debug printouts throughout the process when CONFIG_OF_CONTROL is set?

More questions in this forum