diff --git a/src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/DefaultEthereumMethods.kt b/src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/DefaultEthereumMethods.kt
index 8c5b279f..00a140dc 100644
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/DefaultEthereumMethods.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/DefaultEthereumMethods.kt
@@ -22,6 +22,7 @@ import io.emeraldpay.dshackle.quorum.AlwaysQuorum
 import io.emeraldpay.dshackle.quorum.CallQuorum
 import io.emeraldpay.dshackle.quorum.NotLaggingQuorum
 import io.emeraldpay.dshackle.quorum.NotNullQuorum
+import io.emeraldpay.dshackle.upstream.calls.DefaultEthereumMethods.HardcodedData.Companion.createHardcodedData
 import io.emeraldpay.etherjar.rpc.RpcException
 
 /**
@@ -70,48 +71,48 @@ class DefaultEthereumMethods(
         )
 
         val CHAIN_DATA = mapOf(
-            Chain.ETHEREUM__MAINNET to HardcodedData("\"1\"", "\"0x1\""),
-            Chain.ETHEREUM__RINKEBY to HardcodedData("\"4\"", "\"0x4\""),
-            Chain.ETHEREUM__ROPSTEN to HardcodedData("\"3\"", "\"0x3\""),
-            Chain.ETHEREUM__KOVAN to HardcodedData("\"42\"", "\"0x2a\""),
-            Chain.ETHEREUM__GOERLI to HardcodedData("\"5\"", "\"0x5\""),
-            Chain.ETHEREUM__SEPOLIA to HardcodedData("\"11155111\"", "\"0xaa36a7\""),
+            Chain.ETHEREUM__MAINNET to createHardcodedData("\"1\"", "\"0x1\""),
+            Chain.ETHEREUM__RINKEBY to createHardcodedData("\"4\"", "\"0x4\""),
+            Chain.ETHEREUM__ROPSTEN to createHardcodedData("\"3\"", "\"0x3\""),
+            Chain.ETHEREUM__KOVAN to createHardcodedData("\"42\"", "\"0x2a\""),
+            Chain.ETHEREUM__GOERLI to createHardcodedData("\"5\"", "\"0x5\""),
+            Chain.ETHEREUM__SEPOLIA to createHardcodedData("\"11155111\"", "\"0xaa36a7\""),
 
-            Chain.ETHEREUM_CLASSIC__MAINNET to HardcodedData("\"1\"", "\"0x3d\""),
+            Chain.ETHEREUM_CLASSIC__MAINNET to createHardcodedData("\"1\"", "\"0x3d\""),
 
-            Chain.POLYGON_POS__MAINNET to HardcodedData("\"137\"", "\"0x89\""),
-            Chain.POLYGON_POS__MUMBAI to HardcodedData("\"80001\"", "\"0x13881\""),
+            Chain.POLYGON_POS__MAINNET to createHardcodedData("\"137\"", "\"0x89\""),
+            Chain.POLYGON_POS__MUMBAI to createHardcodedData("\"80001\"", "\"0x13881\""),
 
-            Chain.ARBITRUM__MAINNET to HardcodedData("\"42161\"", "\"0xa4b1\""),
-            Chain.ARBITRUM__GOERLI to HardcodedData("\"421613\"", "\"0x66eed\""),
+            Chain.ARBITRUM__MAINNET to createHardcodedData("\"42161\"", "\"0xa4b1\""),
+            Chain.ARBITRUM__GOERLI to createHardcodedData("\"421613\"", "\"0x66eed\""),
 
-            Chain.OPTIMISM__MAINNET to HardcodedData("\"10\"", "\"0xa\""),
-            Chain.OPTIMISM__GOERLI to HardcodedData("\"420\"", "\"0x1A4\""),
+            Chain.OPTIMISM__MAINNET to createHardcodedData("\"10\"", "\"0xa\""),
+            Chain.OPTIMISM__GOERLI to createHardcodedData("\"420\"", "\"0x1A4\""),
 
-            Chain.ARBITRUM_NOVA__MAINNET to HardcodedData("\"42170\"", "\"0xa4ba\""),
+            Chain.ARBITRUM_NOVA__MAINNET to createHardcodedData("\"42170\"", "\"0xa4ba\""),
 
-            Chain.POLYGON_ZKEVM__MAINNET to HardcodedData("\"1101\"", "\"0x44d\""),
-            Chain.POLYGON_ZKEVM__TESTNET to HardcodedData("\"1442\"", "\"0x5a2\""),
+            Chain.POLYGON_ZKEVM__MAINNET to createHardcodedData("\"1101\"", "\"0x44d\""),
+            Chain.POLYGON_ZKEVM__TESTNET to createHardcodedData("\"1442\"", "\"0x5a2\""),
 
-            Chain.ZKSYNC__MAINNET to HardcodedData("\"324\"", "\"0x144\""),
-            Chain.ZKSYNC__TESTNET to HardcodedData("\"280\"", "\"0x118\""),
+            Chain.ZKSYNC__MAINNET to createHardcodedData("\"324\"", "\"0x144\""),
+            Chain.ZKSYNC__TESTNET to createHardcodedData("\"280\"", "\"0x118\""),
 
-            Chain.BSC__MAINNET to HardcodedData("\"56\"", "\"0x38\""),
+            Chain.BSC__MAINNET to createHardcodedData("\"56\"", "\"0x38\""),
 
-            Chain.BASE__MAINNET to HardcodedData("\"8453\"", "\"0x2105\""),
-            Chain.BASE__GOERLI to HardcodedData("\"84531\"", "\"0x14a33\""),
+            Chain.BASE__MAINNET to createHardcodedData("\"8453\"", "\"0x2105\""),
+            Chain.BASE__GOERLI to createHardcodedData("\"84531\"", "\"0x14a33\""),
 
-            Chain.LINEA__MAINNET to HardcodedData("\"59144\"", "\"0xe708\""),
-            Chain.LINEA__GOERLI to HardcodedData("\"59140\"", "\"0xe704\""),
+            Chain.LINEA__MAINNET to createHardcodedData("\"59144\"", "\"0xe708\""),
+            Chain.LINEA__GOERLI to createHardcodedData("\"59140\"", "\"0xe704\""),
 
-            Chain.FANTOM__MAINNET to HardcodedData("\"250\"", "\"0xfa\""),
-            Chain.FANTOM__TESTNET to HardcodedData("\"4002\"", "\"0xfa2\""),
+            Chain.FANTOM__MAINNET to createHardcodedData("\"250\"", "\"0xfa\""),
+            Chain.FANTOM__TESTNET to createHardcodedData("\"4002\"", "\"0xfa2\""),
 
-            Chain.GNOSIS__MAINNET to HardcodedData("\"100\"", "\"0x64\""),
-            Chain.GNOSIS__CHIADO to HardcodedData("\"10200\"", "\"0x27d8\""),
+            Chain.GNOSIS__MAINNET to createHardcodedData("\"100\"", "\"0x64\""),
+            Chain.GNOSIS__CHIADO to createHardcodedData("\"10200\"", "\"0x27d8\""),
 
-            Chain.AVALANCHE__MAINNET to HardcodedData("\"43114\"", "\"0xa86a\""),
-            Chain.AVALANCHE__FUJI to HardcodedData("\"43113\"", "\"0xa869\""),
+            Chain.AVALANCHE__MAINNET to createHardcodedData("\"43114\"", "\"0xa86a\""),
+            Chain.AVALANCHE__FUJI to createHardcodedData("\"43113\"", "\"0xa869\""),
         )
 
         fun getChainByData(data: HardcodedData) = CHAIN_DATA.entries.find { it.value == data }?.key
@@ -287,8 +288,6 @@ class DefaultEthereumMethods(
         return hardcodedMethods.contains(method)
     }
 
-    data class HardcodedData(val netVersion: String, val chainId: String)
-
     override fun executeHardcoded(method: String): ByteArray {
         // note that the value is in json representation, i.e. if it's a string it should be with quotes,
         // that's why "\"0x0\"", "\"1\"", etc. But just "true" for a boolean, or "[]" for array.
@@ -348,4 +347,14 @@ class DefaultEthereumMethods(
     override fun getSupportedMethods(): Set<String> {
         return allowedMethods.plus(hardcodedMethods).toSortedSet()
     }
+
+    data class HardcodedData private constructor(
+        val netVersion: String,
+        val chainId: String
+    ) {
+        companion object {
+            fun createHardcodedData(netVersion: String, chainId: String): HardcodedData =
+                HardcodedData(netVersion.lowercase(), chainId.lowercase())
+        }
+    }
 }
diff --git a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumUpstreamValidator.kt b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumUpstreamValidator.kt
index d5042c16..7a0f5c50 100644
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumUpstreamValidator.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumUpstreamValidator.kt
@@ -158,7 +158,7 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
 
                 if (!isChainValid) {
                     val actualChain = getChainByData(
-                        DefaultEthereumMethods.HardcodedData(it.t2, it.t1)
+                        DefaultEthereumMethods.HardcodedData.createHardcodedData(it.t2, it.t1)
                     )?.chainName
                     log.warn(
                         "${chain.chainName} is specified for upstream ${upstream.getId()} " +
@@ -194,14 +194,19 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
                 )
             )
             .flatMap(JsonRpcResponse::requireResult)
-            .doOnError {
-                log.warn(
-                    "Error: ${it.message}. Node ${upstream.getId()} is probably incorrectly configured. " +
-                        "You need to set up your return limit to at least 200000. " +
-                        "Erigon config example: https://github.com/ledgerwatch/erigon/blob/d014da4dc039ea97caf04ed29feb2af92b7b129d/cmd/utils/flags.go#L369 "
-                )
-            }
             .map { true }
+            .onErrorResume {
+                if (it.message != null && it.message!!.contains("rpc.returndata.limit")) {
+                    log.warn(
+                        "Error: ${it.message}. Node ${upstream.getId()} is probably incorrectly configured. " +
+                            "You need to set up your return limit to at least 200000. " +
+                            "Erigon config example: https://github.com/ledgerwatch/erigon/blob/d014da4dc039ea97caf04ed29feb2af92b7b129d/cmd/utils/flags.go#L369"
+                    )
+                    Mono.just(false)
+                } else {
+                    Mono.error(it)
+                }
+            }
             .timeout(
                 Defaults.timeoutInternal,
                 Mono.fromCallable { log.error("No response for eth_call limit check from ${upstream.getId()}") }
@@ -209,8 +214,8 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
             )
             .retryRandomBackoff(3, Duration.ofMillis(100), Duration.ofMillis(500)) { ctx ->
                 log.warn(
-                    "error during validateCallLimit for ${upstream.getId()}, iteration ${ctx.iteration()}",
-                    ctx.exception()
+                    "error during validateCallLimit for ${upstream.getId()}, iteration ${ctx.iteration()}, " +
+                        "message ${ctx.exception().message}"
                 )
             }
             .onErrorReturn(false)
@@ -226,8 +231,8 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
             }
             .retryRandomBackoff(3, Duration.ofMillis(100), Duration.ofMillis(500)) { ctx ->
                 log.warn(
-                    "error during old block retrieving for ${upstream.getId()}, iteration ${ctx.iteration()}",
-                    ctx.exception()
+                    "error during old block retrieving for ${upstream.getId()}, iteration ${ctx.iteration()}, " +
+                        "message ${ctx.exception().message}"
                 )
             }
             .map { result ->
@@ -250,8 +255,8 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
             .read(JsonRpcRequest("eth_chainId", emptyList()))
             .retryRandomBackoff(3, Duration.ofMillis(100), Duration.ofMillis(500)) { ctx ->
                 log.warn(
-                    "error during chainId retrieving for ${upstream.getId()}, iteration ${ctx.iteration()}",
-                    ctx.exception()
+                    "error during chainId retrieving for ${upstream.getId()}, iteration ${ctx.iteration()}, " +
+                        "message ${ctx.exception().message}"
                 )
             }
             .doOnError { log.error("Error during execution 'eth_chainId' - ${it.message} for ${upstream.getId()}") }
@@ -264,8 +269,8 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
             .read(JsonRpcRequest("net_version", emptyList()))
             .retryRandomBackoff(3, Duration.ofMillis(100), Duration.ofMillis(500)) { ctx ->
                 log.warn(
-                    "error during netVersion retrieving for ${upstream.getId()}, iteration ${ctx.iteration()}",
-                    ctx.exception()
+                    "error during netVersion retrieving for ${upstream.getId()}, iteration ${ctx.iteration()}, " +
+                        "message ${ctx.exception().message}"
                 )
             }
             .doOnError { log.error("Error during execution 'net_version' - ${it.message} for ${upstream.getId()}") }
diff --git a/src/main/kotlin/io/emeraldpay/dshackle/upstream/rpcclient/JsonRpcHttpClient.kt b/src/main/kotlin/io/emeraldpay/dshackle/upstream/rpcclient/JsonRpcHttpClient.kt
index 6c511e8b..188fac9e 100644
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/rpcclient/JsonRpcHttpClient.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/rpcclient/JsonRpcHttpClient.kt
@@ -112,7 +112,11 @@ class JsonRpcHttpClient(
         val startTime = StopWatch()
         return Mono.just(key)
             .map(JsonRpcRequest::toJson)
-            .doOnNext { startTime.start() }
+            .doOnNext {
+                if (!startTime.isStarted) {
+                    startTime.start()
+                }
+            }
             .flatMap(this@JsonRpcHttpClient::execute)
             .doOnNext {
                 if (startTime.isStarted) {