diff --git a/libraries/AP_OpticalFlow/AP_OpticalFlow_PX4Flow.cpp b/libraries/AP_OpticalFlow/AP_OpticalFlow_PX4Flow.cpp
index 115be975a8..f92562e5a9 100644
--- a/libraries/AP_OpticalFlow/AP_OpticalFlow_PX4Flow.cpp
+++ b/libraries/AP_OpticalFlow/AP_OpticalFlow_PX4Flow.cpp
@@ -55,7 +55,7 @@ AP_OpticalFlow_PX4Flow *AP_OpticalFlow_PX4Flow::detect(OpticalFlow &_frontend)
  */
 bool AP_OpticalFlow_PX4Flow::scan_buses(void)
 {
-    for (uint8_t bus=0; bus<2; bus++) {
+    for (uint8_t bus = 0; bus < 3; bus++) {
 #ifdef HAL_OPTFLOW_PX4FLOW_I2C_BUS
         // only one bus from HAL
         if (bus != HAL_OPTFLOW_PX4FLOW_I2C_BUS) {