diff --git a/src/lattice.cpp b/src/lattice.cpp
index 43712a4..0e83813 100644
--- a/src/lattice.cpp
+++ b/src/lattice.cpp
@@ -2040,6 +2040,29 @@ bool Lattice::program_pubkey_MachXO3D()
 		}
 	}
 
+	/* Programming and Verify the AUTH_EN2 and AUTH_EN1 Fuses..."
+	 * -- This is undocumented (extracted from USB capture) */
+	uint8_t tx_byte = 0x01;
+	wr_rd(0xc4, &tx, 1, NULL, 0);
+	_jtag->set_state(Jtag::RUN_TEST_IDLE);
+	_jtag->toggleClk(2);
+
+	wr_rd(ISC_NOOP, NULL, 0, NULL, 0);
+
+	/* lattice diamond sends this twice... ? */
+	wr_rd(0xc4, &tx, 1, NULL, 0);
+	_jtag->set_state(Jtag::RUN_TEST_IDLE);
+	_jtag->toggleClk(2);
+
+	wr_rd(ISC_NOOP, NULL, 0, NULL, 0);
+
+
+	wr_rd(READ_STATUS_REGISTER_1, NULL, 0, rxkey, 4);
+	_jtag->set_state(Jtag::RUN_TEST_IDLE);
+	_jtag->toggleClk(2);
+
+	printf("Auth Mode: [0x%x]\n", rxkey >> 0x08 & 0x03);
+
 	/* ISC program done 0x5E */
 	printInfo("Write program Done: ", false);
 	if (writeProgramDone() == false) {