diff --git a/afsk/main.c b/afsk/main.c
index 75bed03a..0050b48b 100644
--- a/afsk/main.c
+++ b/afsk/main.c
@@ -412,7 +412,7 @@ int main(int argc, char * argv[]) {
   #endif
 
   // if ((i2c_bus1 == OFF) && (i2c_bus3 == OFF)) {
-  if (i2c_bus1 == OFF) {  // i2c bus 1 can be turned off using raspi-config to enable sim mode without reboot
+  if (i2c_bus3 == OFF) {  // i2c bus 13 can be turned off manually by editing /boot/config.txt
 
     sim_mode = TRUE;