Comment 13 for bug 707047

Without looking at both DT and non-DT boot logs, I suspect the problem is that U-Boot is only reporting 512MB of ram, and stuffing that amount into the /memory node in the DT. It looks like in the non-DT use case, the kernel command line is being used to manually set the RAM layout, probably so that the FB region doesn't get used by the kernel. In the DT, a couple of memreserve blocks are used to the same purpose:

/memreserve/ 0x9D000000 0x03000000; /* Frame buffer */
/memreserve/ 0xB0000000 0x10000000; /* Top 256MB is unaccessable */

I put those memreserve lines in, but I've never done the due diligence to ensure they are actually accurate.