diff --git a/EPD/EPD_driver.c b/EPD/EPD_driver.c
index 74c653e..d55f1c5 100644
--- a/EPD/EPD_driver.c
+++ b/EPD/EPD_driver.c
@@ -31,8 +31,7 @@ uint32_t EPD_BS_PIN = 13;
 uint32_t EPD_EN_PIN = 0xFF;
 uint32_t EPD_LED_PIN = 0xFF;
 
-#define SPI_INSTANCE  0 /**< SPI instance index. */
-static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */
+// Arduino like function wrappers
 
 void pinMode(uint32_t pin, uint32_t mode)
 {
@@ -83,6 +82,7 @@ void delay(uint32_t ms)
     nrf_delay_ms(ms);
 }
 
+// GPIO
 void DEV_Module_Init(void)
 {
     pinMode(EPD_CS_PIN, OUTPUT);
@@ -98,16 +98,6 @@ void DEV_Module_Init(void)
     pinMode(EPD_BS_PIN, OUTPUT);
     digitalWrite(EPD_BS_PIN, LOW);
 
-    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
-    spi_config.sck_pin = EPD_SCLK_PIN;
-    spi_config.mosi_pin = EPD_MOSI_PIN;
-    spi_config.ss_pin = EPD_CS_PIN;
-#if defined(S112)
-    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, NULL, NULL));
-#else
-    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, NULL));
-#endif
-
     digitalWrite(EPD_DC_PIN, LOW);
     digitalWrite(EPD_CS_PIN, LOW);
     digitalWrite(EPD_RST_PIN, HIGH);
@@ -124,21 +114,114 @@ void DEV_Module_Exit(void)
     digitalWrite(EPD_CS_PIN, LOW);
     digitalWrite(EPD_RST_PIN, LOW);
 
-    nrf_drv_spi_uninit(&spi);
+    DEV_SPI_Exit();
 
     EPD_LED_OFF();
 }
 
+// Hardware SPI (write only)
+
+#define SPI_INSTANCE  0 /**< SPI instance index. */
+static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */
+static bool spi_initialized = false;
+
+void DEV_SPI_Init(void)
+{
+    if (spi_initialized) return;
+    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
+    spi_config.sck_pin = EPD_SCLK_PIN;
+    spi_config.mosi_pin = EPD_MOSI_PIN;
+    spi_config.ss_pin = EPD_CS_PIN;
+#if defined(S112)
+    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, NULL, NULL));
+#else
+    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, NULL));
+#endif
+    spi_initialized = true;
+}
+
+void DEV_SPI_Exit(void)
+{
+    if (!spi_initialized) return;
+    nrf_drv_spi_uninit(&spi);
+    spi_initialized = false;
+}
+
 void DEV_SPI_WriteByte(uint8_t value)
 {
+    DEV_SPI_Init();
     APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, &value, 1, NULL, 0));
 }
 
 void DEV_SPI_WriteBytes(uint8_t *value, uint8_t len)
 {
+    DEV_SPI_Init();
     APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, value, len, NULL, 0));
 }
 
+
+// Software SPI (read / write)
+void DEV_SPI_WriteByte_SW(uint8_t data)
+{
+    DEV_SPI_Exit();
+    pinMode(EPD_MOSI_PIN, OUTPUT);
+    digitalWrite(EPD_CS_PIN, LOW);
+    for (int i = 0; i < 8; i++)
+    {
+        if ((data & 0x80) == 0) digitalWrite(EPD_MOSI_PIN, LOW); 
+        else                    digitalWrite(EPD_MOSI_PIN, HIGH);
+
+        data <<= 1;
+        digitalWrite(EPD_SCLK_PIN, HIGH);     
+        digitalWrite(EPD_SCLK_PIN, LOW);
+    }
+    digitalWrite(EPD_CS_PIN, HIGH);
+}
+
+uint8_t DEV_SPI_ReadByte_SW(void)
+{
+    DEV_SPI_Exit();
+    uint8_t j = 0xff;
+    pinMode(EPD_MOSI_PIN, INPUT);
+    digitalWrite(EPD_CS_PIN, LOW);
+    for (int i = 0; i < 8; i++)
+    {
+        j = j << 1;
+        if (digitalRead(EPD_MOSI_PIN))  j = j | 0x01;
+        else                            j = j & 0xfe;
+        
+        digitalWrite(EPD_SCLK_PIN, HIGH);     
+        digitalWrite(EPD_SCLK_PIN, LOW);
+    }
+    digitalWrite(EPD_CS_PIN, HIGH);
+    pinMode(EPD_MOSI_PIN, 1);
+    return j;
+}
+
+void EPD_WriteCommand_SW(uint8_t Reg)
+{
+    digitalWrite(EPD_DC_PIN, LOW);
+    digitalWrite(EPD_CS_PIN, LOW);
+    DEV_SPI_WriteByte_SW(Reg);
+    digitalWrite(EPD_CS_PIN, HIGH);
+}
+
+void EPD_WriteByte_SW(uint8_t Data)
+{
+    digitalWrite(EPD_DC_PIN, HIGH);
+    digitalWrite(EPD_CS_PIN, LOW);
+    DEV_SPI_WriteByte_SW(Data);
+    digitalWrite(EPD_CS_PIN, HIGH);
+}
+
+uint8_t EPD_ReadByte_SW(void)
+{
+    digitalWrite(EPD_DC_PIN, HIGH);
+    return DEV_SPI_ReadByte_SW();
+}
+
+
+// Hardware SPI
 void EPD_WriteCommand(uint8_t Reg)
 {
     digitalWrite(EPD_DC_PIN, LOW);
@@ -170,19 +253,21 @@ void EPD_Reset(uint32_t value, uint16_t duration)
 
 void EPD_WaitBusy(uint32_t value, uint16_t timeout)
 {
-    NRF_LOG_DEBUG("[EPD]: check busy");
+    NRF_LOG_DEBUG("[EPD]: check busy\n");
     while (digitalRead(EPD_BUSY_PIN) == value) {
         if (timeout % 100 == 0) EPD_LED_TOGGLE();
         delay(1);
         timeout--;
         if (timeout == 0) {
-            NRF_LOG_DEBUG("[EPD]: busy timeout!");
+            NRF_LOG_DEBUG("[EPD]: busy timeout!\n");
             break;
         }
     }
-    NRF_LOG_DEBUG("[EPD]: busy release");
+    NRF_LOG_DEBUG("[EPD]: busy release\n");
 }
 
+
+// lED
 void EPD_LED_ON(void)
 {
     if (EPD_LED_PIN != 0xFF)
@@ -201,6 +286,7 @@ void EPD_LED_TOGGLE(void)
         nrf_gpio_pin_toggle(EPD_LED_PIN);
 }
 
+
 extern epd_driver_t epd_driver_4in2;
 extern epd_driver_t epd_driver_4in2bv2;
 
diff --git a/EPD/EPD_driver.h b/EPD/EPD_driver.h
index efda620..fe77a0e 100644
--- a/EPD/EPD_driver.h
+++ b/EPD/EPD_driver.h
@@ -37,12 +37,14 @@ typedef struct
 	uint16_t height;
     void (*init)(void);                               /**< Initialize the e-Paper register */
     void (*clear)(void);                              /**< Clear screen */
-    void (*send_command)(uint8_t Reg);                  /**< send command */
-	void (*send_byte)(uint8_t Reg);                     /**< send byte */
-    void (*send_data)(uint8_t *Data, uint8_t Len);        /**< send data */
+    void (*send_command)(uint8_t Reg);                /**< send command */
+	void (*send_byte)(uint8_t Reg);                   /**< send byte */
+    void (*send_data)(uint8_t *Data, uint8_t Len);    /**< send data */
     void (*write_image)(uint8_t *black, uint8_t *color, uint16_t x, uint16_t y, uint16_t w, uint16_t h); /**< write image */
     void (*refresh)(void);                            /**< Sends the image buffer in RAM to e-Paper and displays */
     void (*sleep)(void);                              /**< Enter sleep mode */
+    int8_t (*read_temp)(void);                        /**< Read temperature from driver chip */
+    void (*force_temp)(int8_t value);                 /**< Force temperature (will trigger OTP LUT switch) */
 } epd_driver_t;
 
 extern uint32_t EPD_MOSI_PIN;
@@ -69,18 +71,30 @@ void digitalWrite(uint32_t pin, uint32_t value);
 uint32_t digitalRead(uint32_t pin);
 void delay(uint32_t ms);
 
+// GPIO
 void DEV_Module_Init(void);
 void DEV_Module_Exit(void);
 
+// Software SPI (read / write)
+void DEV_SPI_WriteByte_SW(uint8_t data);
+uint8_t DEV_SPI_ReadByte_SW(void);
+void EPD_WriteCommand_SW(uint8_t Reg);
+void EPD_WriteByte_SW(uint8_t Data);
+uint8_t EPD_ReadByte_SW(void);
+
+// Hardware SPI (write only)
+void DEV_SPI_Init(void);
+void DEV_SPI_Exit(void);
 void DEV_SPI_WriteByte(uint8_t value);
 void DEV_SPI_WriteBytes(uint8_t *value, uint8_t len);
-
 void EPD_WriteCommand(uint8_t Reg);
 void EPD_WriteByte(uint8_t Data);
 void EPD_WriteData(uint8_t *Data, uint8_t Len);
+
 void EPD_Reset(uint32_t value, uint16_t duration);
 void EPD_WaitBusy(uint32_t value, uint16_t timeout);
 
+// lED
 void EPD_LED_ON(void);
 void EPD_LED_OFF(void);
 void EPD_LED_TOGGLE(void);
diff --git a/EPD/EPD_service.c b/EPD/EPD_service.c
index a1506fc..ee14640 100644
--- a/EPD/EPD_service.c
+++ b/EPD/EPD_service.c
@@ -19,7 +19,8 @@
 #include "nrf_log.h"
 
 #if defined(S112)
-#define EPD_CFG_DEFAULT {0x14, 0x13, 0x06, 0x05, 0x04, 0x03, 0x02, 0x03, 0xFF, 0x12, 0x07}
+#define EPD_CFG_DEFAULT {0x14, 0x13, 0x06, 0x05, 0x04, 0x03, 0x02, 0x03, 0xFF, 0x12, 0x07} // 52811
+//#define EPD_CFG_DEFAULT {0x14, 0x13, 0x12, 0x11, 0x10, 0x0F, 0x0E, 0x03, 0xFF, 0x0D, 0x02} // 52810
 #else
 #define EPD_CFG_DEFAULT {0x05, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x01, 0x07}
 #endif
diff --git a/EPD/UC8176.c b/EPD/UC8176.c
index bc10ec9..91c69e4 100644
--- a/EPD/UC8176.c
+++ b/EPD/UC8176.c
@@ -37,13 +37,29 @@
 static void EPD_4IN2_PowerOn(void)
 {
     EPD_WriteCommand(0x04);
-	delay(50);
+	EPD_WaitBusy(LOW, 100);
 }
 
 static void EPD_4IN2_PowerOff(void)
 {
     EPD_WriteCommand(0x02);
-	EPD_WaitBusy(LOW, 50);
+	EPD_WaitBusy(LOW, 100);
+}
+
+// Read temperature from driver chip
+int8_t EPD_4IN2_Read_Temp(void)
+{
+    EPD_WriteCommand_SW(0x40); // TSC
+    return (int8_t) EPD_ReadByte_SW();
+}
+
+// Force temperature (will trigger OTP LUT switch)
+void EPD_4IN2_Force_Temp(int8_t value)
+{
+    EPD_WriteCommand_SW(0xE0); // CCSET
+    EPD_WriteByte_SW(0x02);
+    EPD_WriteCommand_SW(0xE5); // TSSET
+    EPD_WriteByte_SW(value);
 }
 
 /******************************************************************************
@@ -52,11 +68,14 @@ parameter:
 ******************************************************************************/
 void EPD_4IN2_Refresh(void)
 {
+    NRF_LOG_DEBUG("[EPD]: refresh begin\n");
     EPD_4IN2_PowerOn();
+    NRF_LOG_DEBUG("[EPD]: temperature: %d\n", EPD_4IN2_Read_Temp());
     EPD_WriteCommand(0x12);
     delay(100);
     EPD_WaitBusy(LOW, 20000);
     EPD_4IN2_PowerOff();
+    NRF_LOG_DEBUG("[EPD]: refresh end\n");
 }
 
 /******************************************************************************
@@ -76,10 +95,10 @@ void EPD_4IN2_Init(void)
 
 void EPD_4IN2B_V2_Init(void)
 {
-    EPD_Reset(HIGH, 10);
+    EPD_Reset(HIGH, 200);
 
     EPD_WriteCommand(0x00);
-    EPD_WriteByte(0x0f);
+    EPD_WriteByte(0x0f);		    // 400x300 B/W/R mode, LUT from OTP
 }
 
 /******************************************************************************
@@ -191,6 +210,8 @@ const epd_driver_t epd_driver_4in2 = {
     .write_image = EPD_4IN2_Write_Image,
     .refresh = EPD_4IN2_Refresh,
     .sleep = EPD_4IN2_Sleep,
+    .read_temp = EPD_4IN2_Read_Temp,
+    .force_temp = EPD_4IN2_Force_Temp,
 };
 
 const epd_driver_t epd_driver_4in2bv2 = {
@@ -205,4 +226,6 @@ const epd_driver_t epd_driver_4in2bv2 = {
     .write_image = EPD_4IN2B_V2_Write_Image,
     .refresh = EPD_4IN2_Refresh,
     .sleep = EPD_4IN2_Sleep,
+    .read_temp = EPD_4IN2_Read_Temp,
+    .force_temp = EPD_4IN2_Force_Temp,
 };
diff --git a/GUI/Calendar.c b/GUI/Calendar.c
index d2c745e..546b36c 100644
--- a/GUI/Calendar.c
+++ b/GUI/Calendar.c
@@ -8,7 +8,7 @@
 #if defined(S112)
 #define PAGE_HEIGHT 150
 #else
-#define PAGE_HEIGHT 72
+#define PAGE_HEIGHT 64
 #endif
 static void DrawDateHeader(Adafruit_GFX *gfx, int16_t x, int16_t y, tm_t *tm, struct Lunar_Date *Lunar)
 {
diff --git a/SDK/12.3.0_d7731ad/components/toolchain/arm/arm_startup_nrf51.s b/SDK/12.3.0_d7731ad/components/toolchain/arm/arm_startup_nrf51.s
index 4ca1bce..4f76255 100644
--- a/SDK/12.3.0_d7731ad/components/toolchain/arm/arm_startup_nrf51.s
+++ b/SDK/12.3.0_d7731ad/components/toolchain/arm/arm_startup_nrf51.s
@@ -46,7 +46,7 @@ Heap_Size       EQU __STARTUP_CONFIG_HEAP_SIZE
                 ELIF :DEF: __HEAP_SIZE
 Heap_Size       EQU __HEAP_SIZE
                 ELSE
-Heap_Size       EQU     4096
+Heap_Size       EQU     3600
                 ENDIF
 
                 AREA    HEAP, NOINIT, READWRITE, ALIGN=3