In Aurora 8B10B v10.1 or earlier, the BGRCALOVRD attribute is set as 5'b00000 but it should be set as 5'b11111.
This is a known issue with the Aurora 8B10B core.
This issue is fixed in Aurora 8B10B v10.2 released with VIVADO 2014.1.
In Aurora 8B10B v10.1 or earlier, this attribute needs to be manually updated.
08/04/2014 - Initial Release