Why is rx_freqlocked stuck low after channel reconfiguration when using multiple reconfiguration controllers in Cyclone IV GX devices?

Description

rx_freqlocked may be stuck low after channel reconfiguration when using multiple reconfiguration controllers in Cyclone® IV GX devices due to a bug in Quartus® II software versions 12.0 and earlier.

Resolution

To work around this problem, install Quartus II software version 12.0 or later.