diff --git a/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundBlobDetector.kt b/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundBlobDetector.kt
index 6e83959d..96b502c8 100644
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundBlobDetector.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundBlobDetector.kt
@@ -55,12 +55,16 @@ class BeaconChainLowerBoundBlobDetector(
 
     private fun parseHeadersResponse(data: ByteArray): ChainResponse {
         val node = Global.objectMapper.readValue<JsonNode>(data)
-        if (node.get("code") != null && node.get("message") != null && node.get("code").textValue() == "404") {
-            return ChainResponse(null, ChainCallError(node.get("code").asInt(), node.get("message").asText(), node.get("message").asText()))
+        val codeNode = node.get("code")
+        val messageNode = node.get("message")
+        val is404 = codeNode != null && (codeNode.asInt() == 404 || codeNode.asText() == "404")
+        if (is404 && messageNode != null) {
+            return ChainResponse(null, ChainCallError(404, messageNode.asText(), messageNode.asText()))
         }
-        if (node.get("data").toString() == "[]") {
+        val dataNode = node.get("data")
+        if (dataNode == null || dataNode.isNull || (dataNode.isArray && dataNode.size() == 0)) {
             return ChainResponse(null, ChainCallError(404, notFoundError))
         }
-        return ChainResponse(node.get("data").toString().toByteArray(), null)
+        return ChainResponse(dataNode.toString().toByteArray(), null)
     }
 }
diff --git a/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundBlockDetector.kt b/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundBlockDetector.kt
index d44f2c5c..d3840773 100644
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundBlockDetector.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundBlockDetector.kt
@@ -57,8 +57,11 @@ class BeaconChainLowerBoundBlockDetector(
 
     private fun parseHeadersResponse(data: ByteArray): ChainResponse {
         val node = Global.objectMapper.readValue<JsonNode>(data)
-        if (node.get("code") != null && node.get("message") != null && node.get("code").textValue() == "404") {
-            return ChainResponse(null, ChainCallError(node.get("code").asInt(), node.get("message").asText(), node.get("message").asText()))
+        val codeNode = node.get("code")
+        val messageNode = node.get("message")
+        val is404 = codeNode != null && (codeNode.asInt() == 404 || codeNode.asText() == "404")
+        if (is404 && messageNode != null) {
+            return ChainResponse(null, ChainCallError(404, messageNode.asText(), messageNode.asText()))
         }
         if (node.get("data")?.get("message")?.get("slot") != null) {
             return ChainResponse(node.get("data").toString().toByteArray(), null)
diff --git a/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundEpochDetector.kt b/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundEpochDetector.kt
index 4be97020..bd2fa2f1 100644
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundEpochDetector.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundEpochDetector.kt
@@ -80,10 +80,12 @@ class BeaconChainLowerBoundEpochDetector(
 
     private fun parseHeadersResponse(data: ByteArray): ChainResponse {
         val node = Global.objectMapper.readValue<JsonNode>(data)
-        if (node.get("code") != null && node.get("message") != null && node.get("code").textValue() == "404") {
-            return ChainResponse(null, ChainCallError(node.get("code").asInt(), node.get("message").asText(), node.get("message").asText()))
+        val codeNode = node.get("code")
+        val messageNode = node.get("message")
+        val is404 = codeNode != null && (codeNode.asInt() == 404 || codeNode.asText() == "404")
+        if (is404 && messageNode != null) {
+            return ChainResponse(null, ChainCallError(404, messageNode.asText(), messageNode.asText()))
         }
-
         val jsonData = node.get("data")
         if (jsonData != null) {
             val str = jsonData.toString()
diff --git a/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundStateDetector.kt b/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundStateDetector.kt
index e84fdca5..d68b1c1f 100644
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundStateDetector.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/beaconchain/BeaconChainLowerBoundStateDetector.kt
@@ -54,10 +54,12 @@ class BeaconChainLowerBoundStateDetector(
 
     private fun parseHeadersResponse(data: ByteArray): ChainResponse {
         val node = Global.objectMapper.readValue<JsonNode>(data)
-        if (node.get("code") != null && node.get("message") != null && node.get("code").textValue() == "404") {
-            return ChainResponse(null, ChainCallError(node.get("code").asInt(), node.get("message").asText(), node.get("message").asText()))
+        val codeNode = node.get("code")
+        val messageNode = node.get("message")
+        val is404 = codeNode != null && (codeNode.asInt() == 404 || codeNode.asText() == "404")
+        if (is404 && messageNode != null) {
+            return ChainResponse(null, ChainCallError(404, messageNode.asText(), messageNode.asText()))
         }
-
         val jsonData = node.get("data")
         if (jsonData != null) {
             val str = jsonData.toString()
diff --git a/src/test/kotlin/io/emeraldpay/dshackle/upstream/generic/GenericRpcHeadTest.kt b/src/test/kotlin/io/emeraldpay/dshackle/upstream/generic/GenericRpcHeadTest.kt
index 22511100..2bb09721 100644
--- a/src/test/kotlin/io/emeraldpay/dshackle/upstream/generic/GenericRpcHeadTest.kt
+++ b/src/test/kotlin/io/emeraldpay/dshackle/upstream/generic/GenericRpcHeadTest.kt
@@ -133,7 +133,7 @@ class GenericRpcHeadTest {
             "id",
             BlockValidator.ALWAYS_VALID,
             upstream,
-            Schedulers.boundedElastic(),
+            Schedulers.immediate(),
             EthereumChainSpecific,
             Duration.ofSeconds(5),
         )