diff --git a/src/emu/machine/wozfdc.c b/src/emu/machine/wozfdc.c
index a6f2a10167e..25e549462a4 100644
--- a/src/emu/machine/wozfdc.c
+++ b/src/emu/machine/wozfdc.c
@@ -111,6 +111,7 @@ void wozfdc_device::device_reset()
 	cur_lss.write_position = 0;
 	cur_lss.write_line_active = false;
 	predicted_lss.tm = attotime::never;
+	external_io_select = false;
 }
 
 void wozfdc_device::a3_update_drive_sel()