diff --git a/gcode_process.c b/gcode_process.c
index 8896871..9b8c644 100644
--- a/gcode_process.c
+++ b/gcode_process.c
@@ -326,7 +326,7 @@ void process_gcode_command() {
 				break;
 				// M115- capabilities string
 			case 115:
-				sersendf_P(PSTR("FIRMWARE_NAME:FiveD_on_Arduino FIRMWARE_URL:http%3A//github.com/triffid/FiveD_on_Arduino/ PROTOCOL_VERSION:1.0 MACHINE_TYPE:Mendel EXTRUDER_COUNT:%d TEMP_SENSOR_COUNT:%d HEATER_COUNT:%d"), 1, NUM_TEMP_SENSORS, NUM_HEATERS);
+				sersendf_P(PSTR("FIRMWARE_NAME:FiveD_on_Arduino FIRMWARE_URL:http%%3A//github.com/triffid/FiveD_on_Arduino/ PROTOCOL_VERSION:1.0 MACHINE_TYPE:Mendel EXTRUDER_COUNT:%d TEMP_SENSOR_COUNT:%d HEATER_COUNT:%d"), 1, NUM_TEMP_SENSORS, NUM_HEATERS);
 				// newline is sent from gcode_parse after we return
 				break;