DDR3A memory range problems with 66AK2H12

Hi Bill,

On our custom board, accesses to certain DDR3A memory ranges cause the 66AK2H12 to hang (and a reset or power cycle is needed to recover).   The problem memory ranges are repeatable, and occur whether accessing the memory from a DSP or ARM core.   The problem occurs on both custom boards that we've tested, though the memory ranges aren't the same on both boards.   The ranges are mainly in the upper half of the 1GB Micron DDR3 -- see attached list.   We have no problems with DDR3B memory -- it passes memory tests --  and it is using the same Micron DDR3 part number, has similar PCB routing/layout design, and is using the same DDR3 register settings as DDR3A.   We're currently working around this problem by constraining Linux to operate in the lower 256MB of DDR3A.  

Do you have any ideas for what might be causing this?  Or suggestions to try to fix it?

Note: We made progress since our previous, related postings.   For example, now we are not normally seeing any DDR3 initialization errors in PGSR0 register.   We've pulled DDR3A_REMAP_EN h/w pin 'high', and have been able to run Linux out of DDR3A (though constrained as mentioned above).

thanks,
Scott