diff --git a/Marlin/src/HAL/STM32F1/eeprom_bl24cxx.cpp b/Marlin/src/HAL/STM32F1/eeprom_bl24cxx.cpp
new file mode 100644
index 0000000000..f77306a88a
--- /dev/null
+++ b/Marlin/src/HAL/STM32F1/eeprom_bl24cxx.cpp
@@ -0,0 +1,81 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * 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
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+/**
+ * PersistentStore for Arduino-style EEPROM interface
+ * with simple implementations supplied by Marlin.
+ */
+
+#include "../../inc/MarlinConfig.h"
+
+#if ENABLED(IIC_BL24CXX_EEPROM)
+
+#include "../shared/eeprom_if.h"
+#include "../shared/eeprom_api.h"
+
+//
+// PersistentStore
+//
+
+#ifndef MARLIN_EEPROM_SIZE
+  #error "MARLIN_EEPROM_SIZE is required for IIC_BL24CXX_EEPROM."
+#endif
+
+size_t PersistentStore::capacity()    { return MARLIN_EEPROM_SIZE; }
+
+bool PersistentStore::access_start()  { eeprom_init(); return true; }
+bool PersistentStore::access_finish() { return true; }
+
+bool PersistentStore::write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc) {
+  while (size--) {
+    uint8_t v = *value;
+    uint8_t * const p = (uint8_t * const)pos;
+    // EEPROM has only ~100,000 write cycles,
+    // so only write bytes that have changed!
+    if (v != eeprom_read_byte(p)) {
+      eeprom_write_byte(p, v);
+      delay(2);
+      if (eeprom_read_byte(p) != v) {
+        SERIAL_ECHO_MSG(STR_ERR_EEPROM_WRITE);
+        return true;
+      }
+    }
+    crc16(crc, &v, 1);
+    pos++;
+    value++;
+  }
+  return false;
+}
+
+bool PersistentStore::read_data(int &pos, uint8_t* value, size_t size, uint16_t *crc, const bool writing/*=true*/) {
+  do {
+    uint8_t * const p = (uint8_t * const)pos;
+    uint8_t c = eeprom_read_byte(p);
+    if (writing) *value = c;
+    crc16(crc, &c, 1);
+    pos++;
+    value++;
+  } while (--size);
+  return false;
+}
+
+#endif // IIC_BL24CXX_EEPROM
diff --git a/Marlin/src/HAL/STM32F1/eeprom_if_iic.cpp b/Marlin/src/HAL/STM32F1/eeprom_if_iic.cpp
new file mode 100644
index 0000000000..33dd277add
--- /dev/null
+++ b/Marlin/src/HAL/STM32F1/eeprom_if_iic.cpp
@@ -0,0 +1,51 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * 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
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+/**
+ * Platform-independent Arduino functions for I2C EEPROM.
+ * Enable USE_SHARED_EEPROM if not supplied by the framework.
+ */
+
+#include "../../inc/MarlinConfig.h"
+
+#if ENABLED(IIC_BL24CXX_EEPROM)
+
+#include "../../libs/BL24CXX.h"
+#include "../shared/eeprom_if.h"
+
+void eeprom_init() { BL24CXX::init(); }
+
+// ------------------------
+// Public functions
+// ------------------------
+
+void eeprom_write_byte(uint8_t *pos, unsigned char value) {
+  const unsigned eeprom_address = (unsigned)pos;
+  return BL24CXX::writeOneByte(eeprom_address, value);
+}
+
+uint8_t eeprom_read_byte(uint8_t *pos) {
+  const unsigned eeprom_address = (unsigned)pos;
+  return BL24CXX::readOneByte(eeprom_address);
+}
+
+#endif // IIC_BL24CXX_EEPROM
diff --git a/Marlin/src/HAL/shared/eeprom_api.h b/Marlin/src/HAL/shared/eeprom_api.h
index b97267484e..6445f7a4aa 100644
--- a/Marlin/src/HAL/shared/eeprom_api.h
+++ b/Marlin/src/HAL/shared/eeprom_api.h
@@ -29,20 +29,38 @@
 
 class PersistentStore {
 public:
-  static bool access_start();
-  static bool access_finish();
-  static bool write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc);
-  static bool read_data(int &pos, uint8_t* value, size_t size, uint16_t *crc, const bool writing=true);
+
+  // Total available persistent storage space (in bytes)
   static size_t capacity();
 
+  // Prepare to read or write
+  static bool access_start();
+
+  // Housecleaning after read or write
+  static bool access_finish();
+
+  // Write one or more bytes of data and update the CRC
+  // Return 'true' on write error
+  static bool write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc);
+
+  // Read one or more bytes of data and update the CRC
+  // Return 'true' on read error
+  static bool read_data(int &pos, uint8_t* value, size_t size, uint16_t *crc, const bool writing=true);
+
+  // Write one or more bytes of data
+  // Return 'true' on write error
   static inline bool write_data(const int pos, const uint8_t* value, const size_t size=sizeof(uint8_t)) {
     int data_pos = pos;
     uint16_t crc = 0;
     return write_data(data_pos, value, size, &crc);
   }
 
+  // Write a single byte of data
+  // Return 'true' on write error
   static inline bool write_data(const int pos, const uint8_t value) { return write_data(pos, &value); }
 
+  // Read one or more bytes of data
+  // Return 'true' on read error
   static inline bool read_data(const int pos, uint8_t* value, const size_t size=1) {
     int data_pos = pos;
     uint16_t crc = 0;
diff --git a/Marlin/src/MarlinCore.cpp b/Marlin/src/MarlinCore.cpp
index 55c0bda4ac..7ba577504a 100644
--- a/Marlin/src/MarlinCore.cpp
+++ b/Marlin/src/MarlinCore.cpp
@@ -72,7 +72,7 @@
 #endif
 
 #if ENABLED(IIC_BL24CXX_EEPROM)
-  #include "lcd/dwin/eeprom_BL24CXX.h"
+  #include "libs/BL24CXX.h"
 #endif
 
 #if ENABLED(DIRECT_STEPPING)
@@ -1171,7 +1171,7 @@ void setup() {
   #if ENABLED(IIC_BL24CXX_EEPROM)
     BL24CXX::init();
     const uint8_t err = BL24CXX::check();
-    SERIAL_ECHO_TERNARY(err, "I2C_EEPROM Check ", "failed", "succeeded", "!\n");
+    SERIAL_ECHO_TERNARY(err, "BL24CXX Check ", "failed", "succeeded", "!\n");
   #endif
 
   #if ENABLED(DWIN_CREALITY_LCD)
diff --git a/Marlin/src/gcode/eeprom/M500-M504.cpp b/Marlin/src/gcode/eeprom/M500-M504.cpp
index 4eb6dfcc76..5aee68ba99 100644
--- a/Marlin/src/gcode/eeprom/M500-M504.cpp
+++ b/Marlin/src/gcode/eeprom/M500-M504.cpp
@@ -58,11 +58,47 @@ void GcodeSuite::M502() {
 #endif // !DISABLE_M503
 
 #if ENABLED(EEPROM_SETTINGS)
+
+  #if ENABLED(MARLIN_DEV_MODE)
+    #include "../../libs/hex_print_routines.h"
+  #endif
+
   /**
    * M504: Validate EEPROM Contents
    */
   void GcodeSuite::M504() {
+    #if ENABLED(MARLIN_DEV_MODE)
+      const bool dowrite = parser.seenval('W');
+      if (dowrite || parser.seenval('R')) {
+        uint8_t val = 0;
+        int addr = parser.value_ushort();
+        if (dowrite) {
+          val = parser.byteval('V');
+          persistentStore.write_data(addr, &val);
+          SERIAL_ECHOLNPAIR("Wrote address ", addr, " with ", int(val));
+        }
+        else {
+          if (parser.seenval('T')) {
+            const int endaddr = parser.value_ushort();
+            while (addr <= endaddr) {
+              persistentStore.read_data(addr, &val);
+              SERIAL_ECHOLNPAIR("0x", hex_word(addr), ":", hex_byte(val));
+              addr++;
+              safe_delay(10);
+            }
+            SERIAL_EOL();
+          }
+          else {
+            persistentStore.read_data(addr, &val);
+            SERIAL_ECHOLNPAIR("Read address ", addr, " and got ", int(val));
+          }
+        }
+        return;
+      }
+    #endif
+
     if (settings.validate())
       SERIAL_ECHO_MSG("EEPROM OK");
   }
+
 #endif
diff --git a/Marlin/src/inc/Conditionals_post.h b/Marlin/src/inc/Conditionals_post.h
index 401a64d72d..e12310e07c 100644
--- a/Marlin/src/inc/Conditionals_post.h
+++ b/Marlin/src/inc/Conditionals_post.h
@@ -50,6 +50,8 @@
     #define USE_EMULATED_EEPROM 1
   #elif ANY(I2C_EEPROM, SPI_EEPROM)
     #define USE_WIRED_EEPROM    1
+  #elif ENABLED(IIC_BL24CXX_EEPROM)
+    // nothing
   #else
     #define USE_FALLBACK_EEPROM 1
   #endif
@@ -60,6 +62,7 @@
   #undef SDCARD_EEPROM_EMULATION
   #undef SRAM_EEPROM_EMULATION
   #undef FLASH_EEPROM_EMULATION
+  #undef IIC_BL24CXX_EEPROM
 #endif
 
 #ifdef TEENSYDUINO
diff --git a/Marlin/src/inc/SanityCheck.h b/Marlin/src/inc/SanityCheck.h
index f8e4dc669a..a90571b175 100644
--- a/Marlin/src/inc/SanityCheck.h
+++ b/Marlin/src/inc/SanityCheck.h
@@ -2131,8 +2131,13 @@ static_assert(hbm[Z_AXIS] >= 0, "HOMING_BUMP_MM.Z must be greater than or equal
  */
 #if ENABLED(EEPROM_SETTINGS)
   #if 1 < 0 \
-    + ENABLED(I2C_EEPROM) + ENABLED(SPI_EEPROM) + ENABLED(QSPI_EEPROM) \
-    + ENABLED(SDCARD_EEPROM_EMULATION) + ENABLED(FLASH_EEPROM_EMULATION) + ENABLED(SRAM_EEPROM_EMULATION)
+    + ENABLED(I2C_EEPROM) \
+    + ENABLED(SPI_EEPROM) \
+    + ENABLED(QSPI_EEPROM) \
+    + ENABLED(SDCARD_EEPROM_EMULATION) \
+    + ENABLED(FLASH_EEPROM_EMULATION) \
+    + ENABLED(SRAM_EEPROM_EMULATION) \
+    + ENABLED(IIC_BL24CXX_EEPROM)
     #error "Please select only one method of EEPROM Persistent Storage."
   #endif
 #endif
diff --git a/Marlin/src/lcd/dwin/dwin.cpp b/Marlin/src/lcd/dwin/dwin.cpp
index 4f661ca953..fd2b6810cc 100644
--- a/Marlin/src/lcd/dwin/dwin.cpp
+++ b/Marlin/src/lcd/dwin/dwin.cpp
@@ -185,10 +185,11 @@ int temphot = 0, tempbed = 0;
 float zprobe_zoffset = 0;
 float last_zoffset = 0, last_probe_zoffset = 0;
 
-#define FONT_EEPROM_OFFSET 0
+#define DWIN_LANGUAGE_EEPROM_ADDRESS 0x01   // Between 0x01 and 0x63 (EEPROM_OFFSET-1)
+                                            // BL24CXX::check() uses 0x00
 
 void lcd_select_language(void) {
-  BL24CXX::read(FONT_EEPROM_OFFSET, (uint8_t*)&HMI_flag.language_flag, sizeof(HMI_flag.language_flag));
+  BL24CXX::read(DWIN_LANGUAGE_EEPROM_ADDRESS, (uint8_t*)&HMI_flag.language_flag, sizeof(HMI_flag.language_flag));
   if (HMI_flag.language_flag)
     DWIN_JPG_CacheTo1(Language_Chinese);
   else
@@ -198,12 +199,12 @@ void lcd_select_language(void) {
 void set_english_to_eeprom(void) {
   HMI_flag.language_flag = 0;
   DWIN_JPG_CacheTo1(Language_English);
-  BL24CXX::write(FONT_EEPROM_OFFSET, (uint8_t*)&HMI_flag.language_flag, sizeof(HMI_flag.language_flag));
+  BL24CXX::write(DWIN_LANGUAGE_EEPROM_ADDRESS, (uint8_t*)&HMI_flag.language_flag, sizeof(HMI_flag.language_flag));
 }
 void set_chinese_to_eeprom(void) {
   HMI_flag.language_flag = 1;
   DWIN_JPG_CacheTo1(Language_Chinese);
-  BL24CXX::write(FONT_EEPROM_OFFSET, (uint8_t*)&HMI_flag.language_flag, sizeof(HMI_flag.language_flag));
+  BL24CXX::write(DWIN_LANGUAGE_EEPROM_ADDRESS, (uint8_t*)&HMI_flag.language_flag, sizeof(HMI_flag.language_flag));
 }
 
 void show_plus_or_minus(uint8_t size, uint16_t bColor, uint8_t iNum, uint8_t fNum, uint16_t x, uint16_t y, long value) {
diff --git a/Marlin/src/lcd/dwin/dwin.h b/Marlin/src/lcd/dwin/dwin.h
index e834ef3e24..2d24d2504e 100644
--- a/Marlin/src/lcd/dwin/dwin.h
+++ b/Marlin/src/lcd/dwin/dwin.h
@@ -27,7 +27,7 @@
 
 #include "dwin_lcd.h"
 #include "rotary_encoder.h"
-#include "eeprom_BL24CXX.h"
+#include "../../libs/BL24CXX.h"
 
 #include <stdint.h>
 
diff --git a/Marlin/src/lcd/dwin/eeprom_BL24CXX.cpp b/Marlin/src/lcd/dwin/eeprom_BL24CXX.cpp
deleted file mode 100644
index 25356ab406..0000000000
--- a/Marlin/src/lcd/dwin/eeprom_BL24CXX.cpp
+++ /dev/null
@@ -1,263 +0,0 @@
-/**
- * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
- *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
- *
- * 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
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- *
- */
-
-/********************************************************************************
- * @file     eeprom_BL24CXX.cpp
- * @brief    i2c EEPROM for Ender 3 v2 board (4.2.2)
- ********************************************************************************/
-
-#include "../../inc/MarlinConfig.h"
-
-#if ENABLED(IIC_BL24CXX_EEPROM)
-
-#include "eeprom_BL24CXX.h"
-#include "../../MarlinCore.h"
-
-#include <stdlib.h>
-
-/******************** IIC ********************/
-
-// 初始化IIC
-void IIC::init() {
-  SET_OUTPUT(IIC_EEPROM_SDA);
-  SET_OUTPUT(IIC_EEPROM_SCL);
-
-  IIC_SCL_1();
-  IIC_SDA_1();
-}
-
-// 产生IIC起始信号
-void IIC::start() {
-  SDA_OUT();      // sda线输出
-  IIC_SDA_1();
-  IIC_SCL_1();
-  delay_us(4);
-  IIC_SDA_0(); // START:when CLK is high, DATA change form high to low
-  delay_us(4);
-  IIC_SCL_0(); // 钳住I2C总线,准备发送或接收数据
-}
-
-// 产生IIC停止信号
-void IIC::stop() {
-  SDA_OUT(); // sda线输出
-  IIC_SCL_0();
-  IIC_SDA_0(); // STOP:when CLK is high DATA change form low to high
-  delay_us(4);
-  IIC_SCL_1();
-  IIC_SDA_1(); // 发送I2C总线结束信号
-  delay_us(4);
-}
-
-// 等待应答信号到来
-// 返回值:1,接收应答失败
-//         0,接收应答成功
-uint8_t IIC::wait_ack() {
-  uint8_t ucErrTime=0;
-  SDA_IN();      // SDA设置为输入
-  IIC_SDA_1();delay_us(1);
-  IIC_SCL_1();delay_us(1);
-  while (READ_SDA()) {
-    ucErrTime++;
-    if (ucErrTime>250) {
-      stop();
-      return 1;
-    }
-  }
-  IIC_SCL_0(); // 时钟输出0
-  return 0;
-}
-
-// 产生ACK应答
-void IIC::ack() {
-  IIC_SCL_0();
-  SDA_OUT();
-  IIC_SDA_0();
-  delay_us(2);
-  IIC_SCL_1();
-  delay_us(2);
-  IIC_SCL_0();
-}
-
-// 不产生ACK应答
-void IIC::nAck() {
-  IIC_SCL_0();
-  SDA_OUT();
-  IIC_SDA_1();
-  delay_us(2);
-  IIC_SCL_1();
-  delay_us(2);
-  IIC_SCL_0();
-}
-
-// IIC发送一个字节
-// 返回从机有无应答
-// 1,有应答
-// 0,无应答
-void IIC::send_byte(uint8_t txd) {
-  SDA_OUT();
-  IIC_SCL_0(); // 拉低时钟开始数据传输
-  LOOP_L_N(t, 8) {
-    // IIC_SDA = (txd & 0x80) >> 7;
-    if (txd & 0x80) IIC_SDA_1(); else IIC_SDA_0();
-    txd <<= 1;
-    delay_us(2);   // 对TEA5767这三个延时都是必须的
-    IIC_SCL_1();
-    delay_us(2);
-    IIC_SCL_0();
-    delay_us(2);
-  }
-}
-
-// 读1个字节,ack=1时,发送ACK,ack=0,发送nACK
-uint8_t IIC::read_byte(unsigned char ack_chr) {
-  unsigned char receive = 0;
-  SDA_IN(); // SDA设置为输入
-  LOOP_L_N(i, 8) {
-    IIC_SCL_0();
-    delay_us(2);
-    IIC_SCL_1();
-    receive <<= 1;
-    if (READ_SDA()) receive++;
-    delay_us(1);
-  }
-  ack_chr ? ack() : nAck(); // 发送ACK / 发送nACK
-  return receive;
-}
-
-/******************** EEPROM ********************/
-
-// 初始化IIC接口
-void BL24CXX::init() { IIC::init(); }
-
-// 在BL24CXX指定地址读出一个数据
-// ReadAddr:开始读数的地址
-// 返回值  :读到的数据
-uint8_t BL24CXX::readOneByte(uint16_t ReadAddr) {
-  uint8_t temp = 0;
-  IIC::start();
-  if (EE_TYPE > BL24C16) {
-    IIC::send_byte(0xA0);     // 发送写命令
-    IIC::wait_ack();
-    IIC::send_byte(ReadAddr >> 8); // 发送高地址
-    IIC::wait_ack();
-  }
-  else
-    IIC::send_byte(0xA0 + ((ReadAddr >> 8) << 1));   // 发送器件地址0xA0,写数据
-
-  IIC::wait_ack();
-  IIC::send_byte(ReadAddr & 0xFF); // 发送低地址
-  IIC::wait_ack();
-  IIC::start();
-  IIC::send_byte(0xA1);           // 进入接收模式
-  IIC::wait_ack();
-  temp = IIC::read_byte(0);
-  IIC::stop(); // 产生一个停止条件
-  return temp;
-}
-
-// 在BL24CXX指定地址写入一个数据
-// WriteAddr  :写入数据的目的地址
-// DataToWrite:要写入的数据
-void BL24CXX::writeOneByte(uint16_t WriteAddr, uint8_t DataToWrite) {
-  IIC::start();
-  if (EE_TYPE > BL24C16) {
-    IIC::send_byte(0xA0);      // 发送写命令
-    IIC::wait_ack();
-    IIC::send_byte(WriteAddr >> 8); // 发送高地址
-  }
-  else {
-    IIC::send_byte(0xA0 + ((WriteAddr >> 8) << 1));   // 发送器件地址0xA0,写数据
-  }
-  IIC::wait_ack();
-  IIC::send_byte(WriteAddr & 0xFF); // 发送低地址
-  IIC::wait_ack();
-  IIC::send_byte(DataToWrite);     // 发送字节
-  IIC::wait_ack();
-  IIC::stop(); // 产生一个停止条件
-  delay(10);
-}
-
-// 在BL24CXX里面的指定地址开始写入长度为Len的数据
-// 该函数用于写入16bit或者32bit的数据.
-// WriteAddr  :开始写入的地址
-// DataToWrite:数据数组首地址
-// Len        :要写入数据的长度2,4
-void BL24CXX::writeLenByte(uint16_t WriteAddr, uint32_t DataToWrite, uint8_t Len) {
-  LOOP_L_N(t, Len)
-    writeOneByte(WriteAddr + t, (DataToWrite >> (8 * t)) & 0xFF);
-}
-
-// 在BL24CXX里面的指定地址开始读出长度为Len的数据
-// 该函数用于读出16bit或者32bit的数据.
-// ReadAddr   :开始读出的地址
-// 返回值     :数据
-// Len        :要读出数据的长度2,4
-uint32_t BL24CXX::readLenByte(uint16_t ReadAddr, uint8_t Len) {
-  uint32_t temp = 0;
-  LOOP_L_N(t, Len) {
-    temp <<= 8;
-    temp += readOneByte(ReadAddr + Len - t - 1);
-  }
-  return temp;
-}
-
-// 检查BL24CXX是否正常
-// 这里用了24XX的最后一个地址(255)来存储标志字.
-// 如果用其他24C系列,这个地址要修改
-// 返回1:检测失败
-// 返回0:检测成功
-uint8_t BL24CXX::check() {
-  uint8_t temp;
-  temp = readOneByte(255); // 避免每次开机都写BL24CXX
-  if (temp == 'U') return 0;
-  else { // 排除第一次初始化的情况
-    writeOneByte(255, 'U');
-    temp = readOneByte(255);
-    if (temp == 'U') return 0;
-  }
-  return 1;
-}
-
-// 在BL24CXX里面的指定地址开始读出指定个数的数据
-// ReadAddr :开始读出的地址 对24c02为0~255
-// pBuffer  :数据数组首地址
-// NumToRead:要读出数据的个数
-void BL24CXX::read(uint16_t ReadAddr, uint8_t *pBuffer, uint16_t NumToRead) {
-  while (NumToRead) {
-    *pBuffer++ = readOneByte(ReadAddr++);
-    NumToRead--;
-  }
-}
-
-// 在BL24CXX里面的指定地址开始写入指定个数的数据
-// WriteAddr :开始写入的地址 对24c02为0~255
-// pBuffer   :数据数组首地址
-// NumToWrite:要写入数据的个数
-void BL24CXX::write(uint16_t WriteAddr, uint8_t *pBuffer, uint16_t NumToWrite) {
-  while (NumToWrite--) {
-    writeOneByte(WriteAddr, *pBuffer);
-    WriteAddr++;
-    pBuffer++;
-  }
-}
-
-#endif // IIC_BL24CXX_EEPROM
diff --git a/Marlin/src/libs/BL24CXX.cpp b/Marlin/src/libs/BL24CXX.cpp
new file mode 100644
index 0000000000..d34ed8340f
--- /dev/null
+++ b/Marlin/src/libs/BL24CXX.cpp
@@ -0,0 +1,273 @@
+/**
+ * Marlin 3D Printer Firmware
+ *
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * 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
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "../inc/MarlinConfig.h"
+
+#if ENABLED(IIC_BL24CXX_EEPROM)
+
+/**
+ * PersistentStore for Arduino-style EEPROM interface
+ * with simple implementations supplied by Marlin.
+ */
+
+#include "BL24CXX.h"
+#include <libmaple/gpio.h>
+
+#ifndef EEPROM_WRITE_DELAY
+  #define EEPROM_WRITE_DELAY    10
+#endif
+#ifndef EEPROM_DEVICE_ADDRESS
+  #define EEPROM_DEVICE_ADDRESS (0x50 << 1)
+#endif
+
+// IO direction setting
+#define SDA_IN()  do{ PIN_MAP[IIC_EEPROM_SDA].gpio_device->regs->CRH &= 0XFFFF0FFF; PIN_MAP[IIC_EEPROM_SDA].gpio_device->regs->CRH |= 8 << 12; }while(0)
+#define SDA_OUT() do{ PIN_MAP[IIC_EEPROM_SDA].gpio_device->regs->CRH &= 0XFFFF0FFF; PIN_MAP[IIC_EEPROM_SDA].gpio_device->regs->CRH |= 3 << 12; }while(0)
+
+// IO ops
+#define IIC_SCL_0()   WRITE(IIC_EEPROM_SCL, LOW)
+#define IIC_SCL_1()   WRITE(IIC_EEPROM_SCL, HIGH)
+#define IIC_SDA_0()   WRITE(IIC_EEPROM_SDA, LOW)
+#define IIC_SDA_1()   WRITE(IIC_EEPROM_SDA, HIGH)
+#define READ_SDA()    READ(IIC_EEPROM_SDA)
+
+//
+// Simple IIC interface via libmaple
+//
+
+// Initialize IIC
+void IIC::init() {
+  SET_OUTPUT(IIC_EEPROM_SDA);
+  SET_OUTPUT(IIC_EEPROM_SCL);
+  IIC_SCL_1();
+  IIC_SDA_1();
+}
+
+// Generate IIC start signal
+void IIC::start() {
+  SDA_OUT();    // SDA line output
+  IIC_SDA_1();
+  IIC_SCL_1();
+  delay_us(4);
+  IIC_SDA_0();  // START:when CLK is high, DATA change from high to low
+  delay_us(4);
+  IIC_SCL_0();  // Clamp the I2C bus, ready to send or receive data
+}
+
+// Generate IIC stop signal
+void IIC::stop() {
+  SDA_OUT();    // SDA line output
+  IIC_SCL_0();
+  IIC_SDA_0();  // STOP:when CLK is high DATA change from low to high
+  delay_us(4);
+  IIC_SCL_1();
+  IIC_SDA_1();  // Send I2C bus end signal
+  delay_us(4);
+}
+
+// Wait for the response signal to arrive
+// 1 = failed to receive response
+// 0 = response received
+uint8_t IIC::wait_ack() {
+  uint8_t ucErrTime = 0;
+  SDA_IN();      // SDA is set as input
+  IIC_SDA_1(); delay_us(1);
+  IIC_SCL_1(); delay_us(1);
+  while (READ_SDA()) {
+    if (++ucErrTime > 250) {
+      stop();
+      return 1;
+    }
+  }
+  IIC_SCL_0(); // Clock output 0
+  return 0;
+}
+
+// Generate ACK response
+void IIC::ack() {
+  IIC_SCL_0();
+  SDA_OUT();
+  IIC_SDA_0();
+  delay_us(2);
+  IIC_SCL_1();
+  delay_us(2);
+  IIC_SCL_0();
+}
+
+// No ACK response
+void IIC::nAck() {
+  IIC_SCL_0();
+  SDA_OUT();
+  IIC_SDA_1();
+  delay_us(2);
+  IIC_SCL_1();
+  delay_us(2);
+  IIC_SCL_0();
+}
+
+// Send one IIC byte
+// Return whether the slave responds
+// 1 = there is a response
+// 0 = no response
+void IIC::send_byte(uint8_t txd) {
+  SDA_OUT();
+  IIC_SCL_0(); // Pull down the clock to start data transmission
+  LOOP_L_N(t, 8) {
+    // IIC_SDA = (txd & 0x80) >> 7;
+    if (txd & 0x80) IIC_SDA_1(); else IIC_SDA_0();
+    txd <<= 1;
+    delay_us(2);   // All three delays are necessary for TEA5767
+    IIC_SCL_1();
+    delay_us(2);
+    IIC_SCL_0();
+    delay_us(2);
+  }
+}
+
+// Read 1 byte, when ack=1, send ACK, ack=0, send nACK
+uint8_t IIC::read_byte(unsigned char ack_chr) {
+  unsigned char receive = 0;
+  SDA_IN(); // SDA is set as input
+  LOOP_L_N(i, 8) {
+    IIC_SCL_0();
+    delay_us(2);
+    IIC_SCL_1();
+    receive <<= 1;
+    if (READ_SDA()) receive++;
+    delay_us(1);
+  }
+  ack_chr ? ack() : nAck(); // Send ACK / send nACK
+  return receive;
+}
+
+/******************** EEPROM ********************/
+
+// Initialize the IIC interface
+void BL24CXX::init() { IIC::init(); }
+
+// Read a byte at the specified address
+// ReadAddr: the address to start reading
+// Return: the byte read
+uint8_t BL24CXX::readOneByte(uint16_t ReadAddr) {
+  uint8_t temp = 0;
+  IIC::start();
+  if (EE_TYPE > BL24C16) {
+    IIC::send_byte(EEPROM_DEVICE_ADDRESS);        // Send write command
+    IIC::wait_ack();
+    IIC::send_byte(ReadAddr >> 8);                // Send high address
+    IIC::wait_ack();
+  }
+  else
+    IIC::send_byte(EEPROM_DEVICE_ADDRESS + ((ReadAddr >> 8) << 1)); // Send device address 0xA0, write data
+
+  IIC::wait_ack();
+  IIC::send_byte(ReadAddr & 0xFF);                // Send low address
+  IIC::wait_ack();
+  IIC::start();
+  IIC::send_byte(EEPROM_DEVICE_ADDRESS | 0x01);   // Send byte
+  IIC::wait_ack();
+  temp = IIC::read_byte(0);
+  IIC::stop();                                    // Generate a stop condition
+  return temp;
+}
+
+// Write a data at the address specified by BL24CXX
+// WriteAddr: The destination address for writing data
+// DataToWrite: the data to be written
+void BL24CXX::writeOneByte(uint16_t WriteAddr, uint8_t DataToWrite) {
+  IIC::start();
+  if (EE_TYPE > BL24C16) {
+    IIC::send_byte(EEPROM_DEVICE_ADDRESS);        // Send write command
+    IIC::wait_ack();
+    IIC::send_byte(WriteAddr >> 8);               // Send high address
+  }
+  else
+    IIC::send_byte(EEPROM_DEVICE_ADDRESS + ((WriteAddr >> 8) << 1)); // Send device address 0xA0, write data
+
+  IIC::wait_ack();
+  IIC::send_byte(WriteAddr & 0xFF);               // Send low address
+  IIC::wait_ack();
+  IIC::send_byte(DataToWrite);                    // Receiving mode
+  IIC::wait_ack();
+  IIC::stop();                                    // Generate a stop condition
+  delay(10);
+}
+
+// Start writing data of length Len at the specified address in BL24CXX
+// This function is used to write 16bit or 32bit data.
+// WriteAddr: the address to start writing
+// DataToWrite: the first address of the data array
+// Len: The length of the data to be written 2, 4
+void BL24CXX::writeLenByte(uint16_t WriteAddr, uint32_t DataToWrite, uint8_t Len) {
+  LOOP_L_N(t, Len)
+    writeOneByte(WriteAddr + t, (DataToWrite >> (8 * t)) & 0xFF);
+}
+
+// Start reading data of length Len from the specified address in BL24CXX
+// This function is used to read 16bit or 32bit data.
+// ReadAddr: the address to start reading
+// Return value: data
+// Len: The length of the data to be read 2,4
+uint32_t BL24CXX::readLenByte(uint16_t ReadAddr, uint8_t Len) {
+  uint32_t temp = 0;
+  LOOP_L_N(t, Len) {
+    temp <<= 8;
+    temp += readOneByte(ReadAddr + Len - t - 1);
+  }
+  return temp;
+}
+
+// Check if BL24CXX is normal
+// Return 1: Detection failed
+// return 0: detection is successful
+#define BL24CXX_TEST_ADDRESS 0x00
+#define BL24CXX_TEST_VALUE   0x55
+
+bool BL24CXX::_check() {
+  return (readOneByte(BL24CXX_TEST_ADDRESS) != BL24CXX_TEST_VALUE); // false = success!
+}
+
+bool BL24CXX::check() {
+  if (_check()) {                                           // Value was written? Good EEPROM!
+    writeOneByte(BL24CXX_TEST_ADDRESS, BL24CXX_TEST_VALUE); // Write now and check.
+    return _check();
+  }
+  return false; // success!
+}
+
+// Start reading the specified number of data at the specified address in BL24CXX
+// ReadAddr: The address to start reading is 0~255 for 24c02
+// pBuffer: the first address of the data array
+// NumToRead: the number of data to be read
+void BL24CXX::read(uint16_t ReadAddr, uint8_t *pBuffer, uint16_t NumToRead) {
+  for (; NumToRead; NumToRead--)
+    *pBuffer++ = readOneByte(ReadAddr++);
+}
+
+// Start writing the specified number of data at the specified address in BL24CXX
+// WriteAddr: the address to start writing, 0~255 for 24c02
+// pBuffer: the first address of the data array
+// NumToWrite: the number of data to be written
+void BL24CXX::write(uint16_t WriteAddr, uint8_t *pBuffer, uint16_t NumToWrite) {
+  for (; NumToWrite; NumToWrite--, WriteAddr++)
+    writeOneByte(WriteAddr, *pBuffer++);
+}
+
+#endif // IIC_BL24CXX_EEPROM
diff --git a/Marlin/src/lcd/dwin/eeprom_BL24CXX.h b/Marlin/src/libs/BL24CXX.h
similarity index 65%
rename from Marlin/src/lcd/dwin/eeprom_BL24CXX.h
rename to Marlin/src/libs/BL24CXX.h
index e253cc9be2..b069c196c0 100644
--- a/Marlin/src/lcd/dwin/eeprom_BL24CXX.h
+++ b/Marlin/src/libs/BL24CXX.h
@@ -22,25 +22,12 @@
 #pragma once
 
 /********************************************************************************
- * @file     eeprom_BL24CXX.h
+ * @file     BL24CXX.h
  * @brief    i2c EEPROM for Ender 3 v2 board (4.2.2)
  ********************************************************************************/
 
-#include <libmaple/gpio.h>
-
 /******************** IIC ********************/
 
-//IO direction setting
-#define SDA_IN()  do{ PIN_MAP[IIC_EEPROM_SDA].gpio_device->regs->CRH &= 0XFFFF0FFF; PIN_MAP[IIC_EEPROM_SDA].gpio_device->regs->CRH |= 8 << 12; }while(0)
-#define SDA_OUT() do{ PIN_MAP[IIC_EEPROM_SDA].gpio_device->regs->CRH &= 0XFFFF0FFF; PIN_MAP[IIC_EEPROM_SDA].gpio_device->regs->CRH |= 3 << 12; }while(0)
-
-//IO operation function
-#define IIC_SCL_0()   WRITE(IIC_EEPROM_SCL, LOW)
-#define IIC_SCL_1()   WRITE(IIC_EEPROM_SCL, HIGH)
-#define IIC_SDA_0()   WRITE(IIC_EEPROM_SDA, LOW)
-#define IIC_SDA_1()   WRITE(IIC_EEPROM_SDA, HIGH)
-#define READ_SDA()    READ(IIC_EEPROM_SDA)
-
 class BL24CXX;
 
 // All operation functions of IIC
@@ -55,9 +42,6 @@ protected:
   static uint8_t wait_ack();         // IIC waits for ACK signal
   static void ack();                 // IIC sends ACK signal
   static void nAck();                // IIC does not send ACK signal
-
-  static void write_one_byte(uint8_t daddr, uint8_t addr, uint8_t data);
-  static uint8_t read_one_byte(uint8_t daddr, uint8_t addr);
 };
 
 /******************** EEPROM ********************/
@@ -74,13 +58,15 @@ protected:
 #define EE_TYPE BL24C16
 
 class BL24CXX {
+private:
+  static bool _check();                                                             // Check the device
 public:
-  static void init(); // Initialize IIC
-  static uint8_t check();  // Check the device
-  static uint8_t readOneByte(uint16_t ReadAddr);                       // Read a byte at the specified address
-  static void writeOneByte(uint16_t WriteAddr, uint8_t DataToWrite);   // Write a byte at the specified address
-  static void writeLenByte(uint16_t WriteAddr, uint32_t DataToWrite, uint8_t Len);// The specified address begins to write the data of the specified length
-  static uint32_t readLenByte(uint16_t ReadAddr, uint8_t Len);         // The specified address starts to read the data of the specified length
-  static void write(uint16_t WriteAddr, uint8_t *pBuffer, uint16_t NumToWrite);  // Write the specified length of data from the specified address
-  static void read(uint16_t ReadAddr, uint8_t *pBuffer, uint16_t NumToRead);     // Read the data of the specified length from the specified address
+  static void init();                                                               // Initialize IIC
+  static bool check();                                                              // Check / recheck the device
+  static uint8_t readOneByte(uint16_t ReadAddr);                                    // Read a byte at the specified address
+  static void writeOneByte(uint16_t WriteAddr, uint8_t DataToWrite);                // Write a byte at the specified address
+  static void writeLenByte(uint16_t WriteAddr, uint32_t DataToWrite, uint8_t Len);  // The specified address begins to write the data of the specified length
+  static uint32_t readLenByte(uint16_t ReadAddr, uint8_t Len);                      // The specified address starts to read the data of the specified length
+  static void write(uint16_t WriteAddr, uint8_t *pBuffer, uint16_t NumToWrite);     // Write the specified length of data from the specified address
+  static void read(uint16_t ReadAddr, uint8_t *pBuffer, uint16_t NumToRead);        // Read the data of the specified length from the specified address
 };
diff --git a/Marlin/src/libs/hex_print_routines.cpp b/Marlin/src/libs/hex_print_routines.cpp
index 3ab81e596a..5909ffd7d0 100644
--- a/Marlin/src/libs/hex_print_routines.cpp
+++ b/Marlin/src/libs/hex_print_routines.cpp
@@ -23,7 +23,7 @@
 #include "../inc/MarlinConfig.h"
 #include "../gcode/parser.h"
 
-#if ANY(AUTO_BED_LEVELING_UBL, M100_FREE_MEMORY_WATCHER, DEBUG_GCODE_PARSER, TMC_DEBUG)
+#if ANY(AUTO_BED_LEVELING_UBL, M100_FREE_MEMORY_WATCHER, DEBUG_GCODE_PARSER, TMC_DEBUG, MARLIN_DEV_MODE)
 
   #include "hex_print_routines.h"
 
diff --git a/Marlin/src/pins/stm32f1/pins_CREALITY_V4.h b/Marlin/src/pins/stm32f1/pins_CREALITY_V4.h
index cf7594f784..8a413945b7 100644
--- a/Marlin/src/pins/stm32f1/pins_CREALITY_V4.h
+++ b/Marlin/src/pins/stm32f1/pins_CREALITY_V4.h
@@ -47,12 +47,12 @@
   #if ENABLED(IIC_BL24CXX_EEPROM)
     #define IIC_EEPROM_SDA                  PA11
     #define IIC_EEPROM_SCL                  PA12
-    //#define MARLIN_EEPROM_SIZE 0x4000           // 16Kb (24c16)
+    #define MARLIN_EEPROM_SIZE 0x800              // 2Kb (24C16)
+  #else
+    #define SDCARD_EEPROM_EMULATION               // SD EEPROM until all EEPROM is BL24CXX
+    #define MARLIN_EEPROM_SIZE 0x800              // 2Kb
   #endif
 
-  #define SDCARD_EEPROM_EMULATION                 // SD EEPROM until all EEPROM is BL24CXX
-  #define MARLIN_EEPROM_SIZE 0x1000               // 4Kb
-
   // SPI
   //#define SPI_EEPROM                            // EEPROM on SPI-0
   //#define SPI_CHAN_EEPROM1  ?
diff --git a/buildroot/tests/STM32F103RET6_creality-tests b/buildroot/tests/STM32F103RET6_creality-tests
index f9ae634ebc..ca723c7aa2 100644
--- a/buildroot/tests/STM32F103RET6_creality-tests
+++ b/buildroot/tests/STM32F103RET6_creality-tests
@@ -10,6 +10,7 @@ set -e
 # Build with configs included in the PR
 #
 use_example_configs "Creality/Ender-3 V2"
+opt_enable MARLIN_DEV_MODE
 exec_test $1 $2 "Ender 3 v2"
 
 restore_configs