In some cases, a design might contain an instance of the Debug Bridge IP that appears to prevent the debug flow from successfully inserting a debug hub and the following error might appear:
[Chipscope 16-336] Failed to find or create hub core for debug slave <debug core name>. Insertion of debug hub is not supported when there are instantiated debug bridge cores in either master mode or switch enabled in the design. Either remove debug slave core or instantiate a debug bridge master in the region of the debug slave
This issue occurs because the debug flow detects the presence of a Debug Bridge IP and does not attempt to automatically insert a Debug Hub IP. However, the instance of the Debug Bridge IP in the design is not in the correct mode to connect to a debug core. To resolve this issue, ensure that the design has at least one instance of a Debug Bridge IP in BSCAN-to-Debug Hub mode.