I have a board with DDR4 UDIMM and it is fail calibration around 7 out of 10 reset. Tried to change to other UDIMM device and the results is same.
I can run the emif toolkit when the calibration is pass. I can see the calibration results is good margin. So, i think this is not the margin issue. The emif toolkit is hang when i try to run during calibration is fail.
There is several reasons could cause the DDR4 calibration failure such as Signal integrity issue, Power rails issue , Timing issue.
In the 14. Intel Arria 10 EMIF IP Debugging chapter there is debug guide line and debug check list you would like to go though to narrow down the root cause of calibration failure.
Can you follow the debug guideline at first ?