diff --git a/sources/Android/android-communications/library/src/sdk/java/com/polar/sdk/impl/BDBleApiImpl.kt b/sources/Android/android-communications/library/src/sdk/java/com/polar/sdk/impl/BDBleApiImpl.kt
index 579b63b2..2faf5b76 100644
--- a/sources/Android/android-communications/library/src/sdk/java/com/polar/sdk/impl/BDBleApiImpl.kt
+++ b/sources/Android/android-communications/library/src/sdk/java/com/polar/sdk/impl/BDBleApiImpl.kt
@@ -1520,8 +1520,10 @@ class BDBleApiImpl private constructor(context: Context, features: Set<PolarBleS
     }
 
     override fun doFirstTimeUse(identifier: String, ftuConfig: PolarFirstTimeUseConfig): Completable {
-        return Completable.create { emitter ->
+        return Completable.defer {
             try {
+                BleLogger.d(TAG, "doFirstTimeUse(identifier: $identifier): started")
+                
                 val session = sessionPsFtpClientReady(identifier)
                 val client = session.fetchClient(BlePsFtpUtils.RFC77_PFTP_SERVICE) as BlePsFtpClient?
                         ?: throw PolarServiceNotAvailable()
@@ -1537,7 +1539,7 @@ class BDBleApiImpl private constructor(context: Context, features: Set<PolarBleS
                 }
 
                 val ftuInputStream = ByteArrayInputStream(ftuData)
-                val disposable = client.write(ftuBuilder.build().toByteArray(), ftuInputStream)
+                return@defer client.write(ftuBuilder.build().toByteArray(), ftuInputStream)
                         .concatWith(
                                 Completable.defer {
                                     try {
@@ -1554,6 +1556,8 @@ class BDBleApiImpl private constructor(context: Context, features: Set<PolarBleS
                                             baos.toByteArray()
                                         }
 
+                                        BleLogger.d(TAG, "doFirstTimeUse(identifier: $identifier): write user identifier")
+
                                         val userIdInputStream = ByteArrayInputStream(userIdData)
                                         client.write(userIdBuilder.build().toByteArray(), userIdInputStream)
                                                 .ignoreElements()
@@ -1568,26 +1572,27 @@ class BDBleApiImpl private constructor(context: Context, features: Set<PolarBleS
                                                                     throw IllegalArgumentException("Invalid deviceTime format: ${ftuConfig.deviceTime}", e)
                                                                 }
                                                             }
+                                                            BleLogger.d(TAG, "doFirstTimeUse(identifier: $identifier): set local time")
                                                             setLocalTime(identifier, calendar)
                                                         }
                                                 )
                                     } catch (error: Throwable) {
-                                        BleLogger.e(TAG, "writeUserIdentifier() error: $error")
-                                        emitter.onError(error)
-                                        Completable.complete()
+                                        BleLogger.e(TAG, "doFirstTimeUse(identifier: $identifier): write user identifier error: $error")
+                                        Completable.error(error)
                                     }
                                 }
                         )
+                        .ignoreElements()
                         .doOnComplete {
+                            BleLogger.d(TAG, "doFirstTimeUse(identifier: $identifier): completed")
                             sendTerminateAndStopSyncNotifications(client)
                         }
-                        .subscribe(
-                                { emitter.onComplete() },
-                                { error -> emitter.onError(error) }
-                        )
+                        .doOnError { error ->
+                            BleLogger.e(TAG, "doFirstTimeUse(identifier: $identifier): error $error")
+                        }
             } catch (error: Throwable) {
-                BleLogger.e(TAG, "doConfig() error: $error")
-                emitter.onError(error)
+                BleLogger.e(TAG, "doFirstTimeUse(identifier: $identifier): error $error")
+                return@defer Completable.error(error)
             }
         }
     }