-# include the FT2232 interface config for on-board JTAG interface
-source [find interface/luminary.cfg]
+# NOTE: using the on-board FT2232 JTAG/SWD/SWO interface is optional!
+# so is using it in JTAG mode, as done here.
+# NOTE: older '811-EK boards (before rev C) shouldn't use this.
+source [find interface/ftdi/luminary.cfg]