Stefan wrote:

...

At this point all possibilities are on the table and I'm

looking for any

...

input from anyone with experience (good, bad, or whatever) with this processor and/or designs similar to the Sequoia.

If you scan the U-Boot mailing list for 440EPx/Denali DDR2 problems, you will most likely find some references.

I definitely recommend using the latest U-Boot with the SPD-based Denali code, if you're using DIMM modules.

A smoking gun for us was the timing of the address clocking. Look at the lines on a scope; you may find that the clock is hitting too soon (before the address is stable). (If so, you'll need to delay the clock on your board.)

Hope this helps, Mike