diff --git a/artiq/runtime/bridge.c b/artiq/runtime/bridge.c
index bfe3e1fcf..78c47acfd 100644
--- a/artiq/runtime/bridge.c
+++ b/artiq/runtime/bridge.c
@@ -10,7 +10,9 @@
 static void rtio_output_blind(int channel, int addr, int data)
 {
     rtio_chan_sel_write(channel);
+#ifdef CSR_RTIO_O_ADDRESS_ADDR
     rtio_o_address_write(addr);
+#endif
     rtio_o_data_write(data);
     rtio_o_timestamp_write(rtio_get_counter() + TIME_BUFFER);
     rtio_o_we_write(1);
diff --git a/artiq/runtime/rtio.c b/artiq/runtime/rtio.c
index 92f02f651..09f71d9d4 100644
--- a/artiq/runtime/rtio.c
+++ b/artiq/runtime/rtio.c
@@ -55,7 +55,9 @@ void rtio_output(long long int timestamp, int channel, unsigned int addr,
 
     rtio_chan_sel_write(channel);
     rtio_o_timestamp_write(timestamp);
+#ifdef CSR_RTIO_O_ADDRESS_ADDR
     rtio_o_address_write(addr);
+#endif
     rtio_o_data_write(data);
     rtio_o_we_write(1);
     status = rtio_o_status_read();