diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7e93d79d..df4440a5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+# v6.21.3
+- [#3462](https://github.com/xmrig/xmrig/pull/3462) RandomX: correct memcpy size for JIT initialization.
+
 # v6.21.2
 - The dependencies of all prebuilt releases have been updated. Support for old Ubuntu releases has been dropped.
 - [#2800](https://github.com/xmrig/xmrig/issues/2800) Fixed donation with GhostRider algorithm for builds without KawPow algorithm.
diff --git a/src/base/api/Api.cpp b/src/base/api/Api.cpp
index e0907a84..77f8e4aa 100644
--- a/src/base/api/Api.cpp
+++ b/src/base/api/Api.cpp
@@ -1,6 +1,6 @@
 /* XMRig
- * Copyright (c) 2018-2023 SChernykh   <https://github.com/SChernykh>
- * Copyright (c) 2016-2023 XMRig       <https://github.com/xmrig>, <support@xmrig.com>
+ * Copyright (c) 2018-2024 SChernykh   <https://github.com/SChernykh>
+ * Copyright (c) 2016-2024 XMRig       <https://github.com/xmrig>, <support@xmrig.com>
  *
  *   This program is free software: you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -25,6 +25,8 @@
 #include "base/crypto/keccak.h"
 #include "base/io/Env.h"
 #include "base/io/json/Json.h"
+#include "base/io/log/Log.h"
+#include "base/io/log/Tags.h"
 #include "base/kernel/Base.h"
 #include "base/tools/Chrono.h"
 #include "base/tools/Cvt.h"
@@ -39,7 +41,6 @@
 
 
 #include <thread>
-#include <iostream>
 
 
 namespace xmrig {
@@ -81,8 +82,7 @@ static rapidjson::Value getResources(rapidjson::Document &doc)
 
 xmrig::Api::Api(Base *base) :
     m_base(base),
-    m_timestamp(Chrono::currentMSecsSinceEpoch()),
-    m_httpd(nullptr)
+    m_timestamp(Chrono::currentMSecsSinceEpoch())
 {
     base->addListener(this);
 
@@ -118,7 +118,8 @@ void xmrig::Api::start()
     if (!m_httpd) {
         m_httpd = new Httpd(m_base);
         if (!m_httpd->start()) {
-            std::cerr << "HTTP server failed to start." << std::endl;
+            LOG_ERR("%s " RED_BOLD("HTTP API server failed to start."), Tags::network());
+
             delete m_httpd; // Properly handle failure to start
             m_httpd = nullptr;
         }
diff --git a/src/base/api/Api.h b/src/base/api/Api.h
index 7c686ff4..f3ad04c1 100644
--- a/src/base/api/Api.h
+++ b/src/base/api/Api.h
@@ -1,6 +1,6 @@
 /* XMRig
- * Copyright (c) 2018-2023 SChernykh   <https://github.com/SChernykh>
- * Copyright (c) 2016-2023 XMRig       <https://github.com/xmrig>, <support@xmrig.com>
+ * Copyright (c) 2018-2024 SChernykh   <https://github.com/SChernykh>
+ * Copyright (c) 2016-2024 XMRig       <https://github.com/xmrig>, <support@xmrig.com>
  *
  *   This program is free software: you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
diff --git a/src/crypto/randomx/jit_compiler_a64.cpp b/src/crypto/randomx/jit_compiler_a64.cpp
index faaaa853..c9a9cbcf 100644
--- a/src/crypto/randomx/jit_compiler_a64.cpp
+++ b/src/crypto/randomx/jit_compiler_a64.cpp
@@ -1078,6 +1078,6 @@ void JitCompilerA64::h_NOP(Instruction& instr, uint32_t& codePos)
 {
 }
 
-InstructionGeneratorA64 JitCompilerA64::engine[257] = {};
+InstructionGeneratorA64 JitCompilerA64::engine[256] = {};
 
 }
diff --git a/src/crypto/randomx/jit_compiler_a64.hpp b/src/crypto/randomx/jit_compiler_a64.hpp
index 15c90af8..32ff5166 100644
--- a/src/crypto/randomx/jit_compiler_a64.hpp
+++ b/src/crypto/randomx/jit_compiler_a64.hpp
@@ -74,7 +74,7 @@ namespace randomx {
 		void enableWriting() const;
 		void enableExecution() const;
 
-		static InstructionGeneratorA64 engine[257];
+		static InstructionGeneratorA64 engine[256];
 
 	private:
 		const bool hugePages;
diff --git a/src/crypto/randomx/jit_compiler_x86.cpp b/src/crypto/randomx/jit_compiler_x86.cpp
index b9c26af2..73ea105d 100644
--- a/src/crypto/randomx/jit_compiler_x86.cpp
+++ b/src/crypto/randomx/jit_compiler_x86.cpp
@@ -1456,6 +1456,6 @@ namespace randomx {
 		emitByte(0x90, code, codePos);
 	}
 
-	alignas(64) InstructionGeneratorX86 JitCompilerX86::engine[257] = {};
+	alignas(64) InstructionGeneratorX86 JitCompilerX86::engine[256] = {};
 
 }
diff --git a/src/crypto/randomx/jit_compiler_x86.hpp b/src/crypto/randomx/jit_compiler_x86.hpp
index 11106b2f..15261922 100644
--- a/src/crypto/randomx/jit_compiler_x86.hpp
+++ b/src/crypto/randomx/jit_compiler_x86.hpp
@@ -81,7 +81,7 @@ namespace randomx {
 		void enableWriting() const;
 		void enableExecution() const;
 
-		alignas(64) static InstructionGeneratorX86 engine[257];
+		alignas(64) static InstructionGeneratorX86 engine[256];
 
 	private:
 		int registerUsage[RegistersCount] = {};
diff --git a/src/crypto/randomx/randomx.cpp b/src/crypto/randomx/randomx.cpp
index 129798d7..3e229eb4 100644
--- a/src/crypto/randomx/randomx.cpp
+++ b/src/crypto/randomx/randomx.cpp
@@ -301,7 +301,7 @@ typedef void(randomx::JitCompilerX86::* InstructionGeneratorX86_2)(const randomx
 
 #define JIT_HANDLE(x, prev) do { \
 		const InstructionGeneratorX86_2 p = &randomx::JitCompilerX86::h_##x; \
-		memcpy(randomx::JitCompilerX86::engine + k, &p, sizeof(p)); \
+		memcpy(randomx::JitCompilerX86::engine + k, &p, sizeof(randomx::JitCompilerX86::engine[k])); \
 	} while (0)
 
 #elif (XMRIG_ARM == 8)
diff --git a/src/version.h b/src/version.h
index d148b9e2..af575874 100644
--- a/src/version.h
+++ b/src/version.h
@@ -22,7 +22,7 @@
 #define APP_ID        "xmrig"
 #define APP_NAME      "XMRig"
 #define APP_DESC      "XMRig miner"
-#define APP_VERSION   "6.21.2-mo1"
+#define APP_VERSION   "6.21.3-mo1"
 #define APP_DOMAIN    "xmrig.com"
 #define APP_SITE      "www.xmrig.com"
 #define APP_COPYRIGHT "Copyright (C) 2016-2024 xmrig.com"
@@ -30,7 +30,7 @@
 
 #define APP_VER_MAJOR  6
 #define APP_VER_MINOR  21
-#define APP_VER_PATCH  2
+#define APP_VER_PATCH  3
 
 #ifdef _MSC_VER
 #   if (_MSC_VER >= 1930)