For troubleshooting purposes, we generated a script to initialize DDR3 to use a 400MHz (instead of 533MHz) clock using the v1.9 Freescale Register Aid tool (latest as of 12/5/15). We verified the 400MHz initialization script was indeed different from a 533MHz script generated by the same tool. However, after using the 400MHz script to initialize DDR, the clock frequency remains at 533MHz by o-scope measurement (we saw this issue before with the old register scripting aid too). Because the clock frequency does not change there is no way we can try a lower frequency for troubleshooting our DDR3. Is there something additional that needs to be done in order to get the 400MHz clock frequency or is this an indication of a larger issue with our i.MX6Q?