diff --git a/fw/Core/Src/main.c b/fw/Core/Src/main.c
index 7e4af4e..0b6b61b 100644
--- a/fw/Core/Src/main.c
+++ b/fw/Core/Src/main.c
@@ -72,42 +72,41 @@ const uint16_t tim21_period = MEASUREMENT_PERIOD_S * (SYSTEM_CLOCK_HZ / tim21_pr
 /* Input registers memory map implementation */
 enum
 {
-	REGISTER_NUM_T = 30010, /* deg C */
-	REGISTER_NUM_T_F = 30011, /* deg F */
-	REGISTER_NUM_RH = 30012, /* %, from SHT4x */
-	REGISTER_NUM_CO2 = 30013, /* ppm */
-	REGISTER_NUM_VOC_INDEX = 30014, /* VOC index as calculated by Sensirion library (1 to 500, average 100) */
-	REGISTER_NUM_VOC_TICKS = 30015, /* raw VOC ticks */
-	REGISTER_NUM_NOX_INDEX = 30016,
-	REGISTER_NUM_NOX_TICKS = 30017,
-	REGISTER_NUM_PMC_MASS_1_0 = 30018, /* ug / m^3 */
-	REGISTER_NUM_PMC_MASS_2_5 = 30019, /* ug / m^3 */
-	REGISTER_NUM_PMC_MASS_4_0 = 30020, /* ug / m^3 */
-	REGISTER_NUM_PMC_MASS_10_0 = 30021, /* ug / m^3 */
-	REGISTER_NUM_PMC_NUMBER_0_5 = 30022, /* 1 / m^3 */
-	REGISTER_NUM_PMC_NUMBER_1_0 = 30023, /* 1 / m^3 */
-	REGISTER_NUM_PMC_NUMBER_2_5 = 30024, /* 1 / m^3 */
-	REGISTER_NUM_PMC_NUMBER_4_0 = 30025, /* 1 / m^3 */
-	REGISTER_NUM_PMC_NUMBER_10_0 = 30026, /* 1 / m^3 */
-	REGISTER_NUM_TYPICAL_PARTICLE_SIZE = 30027, /* nm */
-	REGISTER_NUM_T_SCD4x = 30028, /* deg C */
-	REGISTER_NUM_T_SCD4x_F = 30029, /* deg F */
-	REGISTER_NUM_RH_SCD4x = 30030, /* % */
-	REGISTER_NUM_DEVICE_IDENTIFIER = 30100
+	REGISTER_NUM_SERIAL_NUMBER_1 = 30001,
+	REGISTER_NUM_SERIAL_NUMBER_2 = 30002,
+	REGISTER_NUM_T = 30003, /* deg C */
+	REGISTER_NUM_T_F = 30004, /* deg F */
+	REGISTER_NUM_RH = 30005, /* %, from SHT4x */
+	REGISTER_NUM_CO2 = 30006, /* ppm */
+	REGISTER_NUM_VOC_INDEX = 30007, /* VOC index as calculated by Sensirion library (1 to 500, average 100) */
+	REGISTER_NUM_VOC_TICKS = 30008, /* raw VOC ticks */
+	REGISTER_NUM_PMC_MASS_1_0 = 30009, /* ug / m^3 */
+	REGISTER_NUM_PMC_MASS_2_5 = 30010, /* ug / m^3 */
+	REGISTER_NUM_PMC_MASS_4_0 = 30011, /* ug / m^3 */
+	REGISTER_NUM_PMC_MASS_10_0 = 30012, /* ug / m^3 */
+	REGISTER_NUM_PMC_NUMBER_0_5 = 30013, /* 1 / m^3 */
+	REGISTER_NUM_PMC_NUMBER_1_0 = 30014, /* 1 / m^3 */
+	REGISTER_NUM_PMC_NUMBER_2_5 = 30015, /* 1 / m^3 */
+	REGISTER_NUM_PMC_NUMBER_4_0 = 30016, /* 1 / m^3 */
+	REGISTER_NUM_PMC_NUMBER_10_0 = 30017, /* 1 / m^3 */
+	REGISTER_NUM_TYPICAL_PARTICLE_SIZE = 30018, /* nm */
+	REGISTER_NUM_T_SCD4x = 30019, /* deg C */
+	REGISTER_NUM_T_SCD4x_F = 30020, /* deg F */
+	REGISTER_NUM_RH_SCD4x = 30021 /* % */
 	/* VOC Index has initial blackout beriod, when the data is not ready. VOC index is 0 during this period */
 } data_registers_numbers;
 
 enum
 {
-	REGISTER_NUM_LED_ON = 40001,
-	REGISTER_NUM_LED_BRIGHTNESS = 40002,
-	REGISTER_NUM_LED_SMOOTH = 40003,
-	REGISTER_NUM_CO2_ALERT_LIMIT1 = 40004,
-	REGISTER_NUM_CO2_ALERT_LIMIT2 = 40005,
-	REGISTER_NUM_SCD4x_T_OFFSET = 40006,
-	REGISTER_NUM_MODBUS_ADDR = 40007,
-	REGISTER_NUM_BAUDRATE = 40008,
-	REGISTER_NUM_RESET_DEVICE = 40100
+	REGISTER_NUM_MODBUS_ADDR = 40001,
+	REGISTER_NUM_BAUDRATE = 40002,
+	REGISTER_NUM_LED_ON = 40003,
+	REGISTER_NUM_LED_BRIGHTNESS = 40004,
+	REGISTER_NUM_LED_SMOOTH = 40005,
+	REGISTER_NUM_CO2_ALERT_LIMIT1 = 40006,
+	REGISTER_NUM_CO2_ALERT_LIMIT2 = 40007,
+	REGISTER_NUM_SCD4x_T_OFFSET = 40008,
+	REGISTER_NUM_RESET_DEVICE = 49999
 } config_registers_numbers;
 
 enum
@@ -1047,8 +1046,6 @@ int8_t modbus_slave_callback(modbus_transaction_t *transaction)
 					case REGISTER_NUM_RH_SCD4x:
 						transaction->input_registers[i] = (uint16_t)RH_SCD4x;
 						break;
-					case REGISTER_NUM_DEVICE_IDENTIFIER:
-						transaction->input_registers[i] = (uint16_t)device_identifier;
 					default:
 						return MODBUS_ERROR_FUNCTION_NOT_IMPLEMENTED;
 				}