diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/sony/headphones/SonyHeadphonesIoThread.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/sony/headphones/SonyHeadphonesIoThread.java
index 975543a1b..88d8b6bcf 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/sony/headphones/SonyHeadphonesIoThread.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/sony/headphones/SonyHeadphonesIoThread.java
@@ -41,8 +41,7 @@ public class SonyHeadphonesIoThread extends BtClassicIoThread {
 
     private final SonyHeadphonesProtocol mProtocol;
 
-    // Track whether we got the first reply
-    private boolean firstReply = false;
+    // Track whether we got the first init reply
     private final Handler handler = new Handler();
     private int initRetries = 0;
 
@@ -53,7 +52,7 @@ public class SonyHeadphonesIoThread extends BtClassicIoThread {
     private final Runnable initSendRunnable = new Runnable() {
         public void run() {
             // If we still haven't got any reply, re-send the init
-            if (!firstReply) {
+            if (!mProtocol.hasProtocolImplementation()) {
                 if (initRetries++ < 2) {
                     LOG.warn("Init retry {}", initRetries);
 
@@ -103,8 +102,6 @@ public class SonyHeadphonesIoThread extends BtClassicIoThread {
             msgStream.write(incoming);
         } while (incoming[0] != Message.MESSAGE_TRAILER);
 
-        firstReply = true;
-
         LOG.trace("Raw message: {}", GB.hexdump(msgStream.toByteArray()));
 
         return msgStream.toByteArray();
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/sony/headphones/SonyHeadphonesProtocol.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/sony/headphones/SonyHeadphonesProtocol.java
index 41b6d9a08..8c28ca291 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/sony/headphones/SonyHeadphonesProtocol.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/sony/headphones/SonyHeadphonesProtocol.java
@@ -104,9 +104,10 @@ public class SonyHeadphonesProtocol extends GBDeviceProtocol {
                 } else if (message.getPayload().length == 6) {
                     LOG.warn("Sony Headphones protocol v2 is not yet supported");
                     return null;
+                } else {
+                    LOG.error("Unexpected init response payload length: {}", message.getPayload().length);
+                    return null;
                 }
-
-                return null;
             }
         }
 
@@ -260,6 +261,10 @@ public class SonyHeadphonesProtocol extends GBDeviceProtocol {
         return requestQueue.remove().encode(sequenceNumber);
     }
 
+    public boolean hasProtocolImplementation() {
+        return protocolImpl != null;
+    }
+
     private GBDeviceEvent handleAck() {
         pendingAcks--;