You can view and change the BSCAN user scan chain index of the debug core hub by selecting the dbg_hub in the Debug window, selecting the Debug Core Options view in the Properties window, then changing the value of the C_USER_SCAN_CHAIN property (see the following figure).
Important: The default values for C_USER_SCAN_CHAIN is 1 for the debug hub core. If using a scan chain value other than 1 for the debug hub core, you must manually change them on the device in the Hardware Manager. Refer to Programming the Hardware Device for more details.
Important: If you plan to use the Microprocessor Debug Module (MDM) or other IP that uses the BSCAN primitive with the Vivado logic debug cores, you need to set the C_USER_SCAN_CHAIN property of the dbg_hub to a user scan chain that does not conflict with the other IPs Boundary Scan Chain setting. Failure to do so results in errors later in the implementation flow.
Figure 1. Changing the User Scan Chain Property of the Debug Core Hub