diff --git a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/EthFeeHistory.java b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/EthFeeHistory.java
index 26e414acda9..92d42f22784 100644
--- a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/EthFeeHistory.java
+++ b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/EthFeeHistory.java
@@ -88,9 +88,15 @@ public String getName() {
   public JsonRpcResponse response(final JsonRpcRequestContext request) {
     final Object requestId = request.getRequest().getId();
 
-    final int blockCount = request.getRequiredParameter(0, UnsignedIntParameter.class).getValue();
+    final int blockCount;
+    try {
+      blockCount = request.getRequiredParameter(0, UnsignedIntParameter.class).getValue();
+    } catch (Exception e) { // TODO:replace with JsonRpcParameter.JsonRpcParameterException
+      throw new InvalidJsonRpcParameters(
+          "Invalid block count parameter (index 0)", RpcErrorType.INVALID_BLOCK_COUNT_PARAMS, e);
+    }
     if (isInvalidBlockCount(blockCount)) {
-      return new JsonRpcErrorResponse(requestId, RpcErrorType.INVALID_PARAMS);
+      return new JsonRpcErrorResponse(requestId, RpcErrorType.INVALID_BLOCK_COUNT_PARAMS);
     }
     final BlockParameter highestBlock;
     try {
@@ -99,6 +105,7 @@ public JsonRpcResponse response(final JsonRpcRequestContext request) {
       throw new InvalidJsonRpcParameters(
           "Invalid highest block parameter (index 1)", RpcErrorType.INVALID_BLOCK_PARAMS, e);
     }
+
     final Optional<List<Double>> maybeRewardPercentiles =
         request.getOptionalParameter(2, Double[].class).map(Arrays::asList);
 
diff --git a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/EngineGetPayloadBodiesByRangeV1.java b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/EngineGetPayloadBodiesByRangeV1.java
index 5fdd1657f67..88431dd89bd 100644
--- a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/EngineGetPayloadBodiesByRangeV1.java
+++ b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/EngineGetPayloadBodiesByRangeV1.java
@@ -17,6 +17,7 @@
 import org.hyperledger.besu.ethereum.ProtocolContext;
 import org.hyperledger.besu.ethereum.api.jsonrpc.RpcMethod;
 import org.hyperledger.besu.ethereum.api.jsonrpc.internal.JsonRpcRequestContext;
+import org.hyperledger.besu.ethereum.api.jsonrpc.internal.exception.InvalidJsonRpcParameters;
 import org.hyperledger.besu.ethereum.api.jsonrpc.internal.methods.ExecutionEngineJsonRpcMethod;
 import org.hyperledger.besu.ethereum.api.jsonrpc.internal.parameters.UnsignedLongParameter;
 import org.hyperledger.besu.ethereum.api.jsonrpc.internal.response.JsonRpcErrorResponse;
@@ -59,7 +60,13 @@ public JsonRpcResponse syncResponse(final JsonRpcRequestContext request) {
 
     final long startBlockNumber =
         request.getRequiredParameter(0, UnsignedLongParameter.class).getValue();
-    final long count = request.getRequiredParameter(1, UnsignedLongParameter.class).getValue();
+    final long count;
+    try {
+      count = request.getRequiredParameter(1, UnsignedLongParameter.class).getValue();
+    } catch (Exception e) { // TODO:replace with JsonRpcParameter.JsonRpcParameterException
+      throw new InvalidJsonRpcParameters(
+          "Invalid block count params (index 1)", RpcErrorType.INVALID_BLOCK_COUNT_PARAMS, e);
+    }
     final Object reqId = request.getRequest().getId();
 
     LOG.atTrace()
diff --git a/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/EthFeeHistoryTest.java b/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/EthFeeHistoryTest.java
index a0821abf2de..0ed7e133822 100644
--- a/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/EthFeeHistoryTest.java
+++ b/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/EthFeeHistoryTest.java
@@ -241,11 +241,11 @@ public void blockCountBounds() {
     assertThat(
             ((JsonRpcErrorResponse) feeHistoryRequest("0x0", "latest", new double[] {100.0}))
                 .getErrorType())
-        .isEqualTo(RpcErrorType.INVALID_PARAMS);
+        .isEqualTo(RpcErrorType.INVALID_BLOCK_COUNT_PARAMS);
     assertThat(
             ((JsonRpcErrorResponse) feeHistoryRequest("0x401", "latest", new double[] {100.0}))
                 .getErrorType())
-        .isEqualTo(RpcErrorType.INVALID_PARAMS);
+        .isEqualTo(RpcErrorType.INVALID_BLOCK_COUNT_PARAMS);
   }
 
   @Test
diff --git a/ethereum/retesteth/src/main/java/org/hyperledger/besu/ethereum/retesteth/methods/TestMineBlocks.java b/ethereum/retesteth/src/main/java/org/hyperledger/besu/ethereum/retesteth/methods/TestMineBlocks.java
index 3060b326bb8..7907cee3f78 100644
--- a/ethereum/retesteth/src/main/java/org/hyperledger/besu/ethereum/retesteth/methods/TestMineBlocks.java
+++ b/ethereum/retesteth/src/main/java/org/hyperledger/besu/ethereum/retesteth/methods/TestMineBlocks.java
@@ -16,9 +16,11 @@
 
 import org.hyperledger.besu.ethereum.ProtocolContext;
 import org.hyperledger.besu.ethereum.api.jsonrpc.internal.JsonRpcRequestContext;
+import org.hyperledger.besu.ethereum.api.jsonrpc.internal.exception.InvalidJsonRpcParameters;
 import org.hyperledger.besu.ethereum.api.jsonrpc.internal.methods.JsonRpcMethod;
 import org.hyperledger.besu.ethereum.api.jsonrpc.internal.response.JsonRpcResponse;
 import org.hyperledger.besu.ethereum.api.jsonrpc.internal.response.JsonRpcSuccessResponse;
+import org.hyperledger.besu.ethereum.api.jsonrpc.internal.response.RpcErrorType;
 import org.hyperledger.besu.ethereum.blockcreation.PoWBlockCreator;
 import org.hyperledger.besu.ethereum.chain.MutableBlockchain;
 import org.hyperledger.besu.ethereum.core.Block;
@@ -44,7 +46,13 @@ public String getName() {
 
   @Override
   public JsonRpcResponse response(final JsonRpcRequestContext requestContext) {
-    long blocksToMine = requestContext.getRequiredParameter(0, Long.class);
+    long blocksToMine = 0;
+    try {
+      blocksToMine = requestContext.getRequiredParameter(0, Long.class);
+    } catch (Exception e) { // TODO:replace with JsonRpcParameter.JsonRpcParameterException
+      throw new InvalidJsonRpcParameters(
+          "Invalid blocks to mine (index 0)", RpcErrorType.INVALID_BLOCK_COUNT_PARAMS, e);
+    }
     while (blocksToMine-- > 0) {
       if (!mineNewBlock()) {
         return new JsonRpcSuccessResponse(requestContext.getRequest().getId(), false);