Version Found: RLDRAM3 v1.4 (Rev 1,2 & 3)
Version Resolved: See (Xilinx Answer 69037)
Due to changes in the IP in 2016.4 and 2017.x Vivado tools, users of the RLDRAM3 controller could experience intermittent calibration failures on an interface that previously passed calibration.
Failures from this issue will only occur during DM DQ Deskew. The change is causing the logic to perform the deskew sanity check on bytes that have not been deskewed.
Therefore, the issue would only arise during the sanity check stage.
Please use the attached patch if you are experiencing the above symptoms.
If that does not correct the issue, please contact Xilinx Technical Support.