NRF51422 I2C sensor (TWI)

Question

Hello everyone,
I have an external board with processor nrf51422 and sensor BNO055 (I2C).
I have a processor code created by someone else and I have a problem getting data from the sensor. I know that similar topics have already appeared on the forum, but despite many attempts I have not managed to establish communication.

I receive "some" data, but they are not logical and change all the time. For example, when I try to read the sensor temperature, I get the values 0x0090, then 0x2003, then 0x0003, then 0x2000, etc.

So I present the original, theoretically working version of Twi_functions. Twi_functions.c 
 #include "twi_functions.h"

/* TWI instance. */
const nrf_drv_twi_t twi_sensors_instance = NRF_DRV_TWI_INSTANCE(1);

void twi_init (void)
{
 ret_code_t err_code;

 const nrf_drv_twi_config_t twi_sensors_config = {
 .scl = I2C_SENSORS_SCL_PIN,
 .sda = I2C_SENSORS_SDA_PIN,
 .frequency = NRF_TWI_FREQ_100K,
 .interrupt_priority = APP_IRQ_PRIORITY_LOW
 };

 err_code = nrf_drv_twi_init(&twi_sensors_instance, &twi_sensors_config, NULL, NULL);
 APP_ERROR_CHECK(err_code);

 nrf_drv_twi_enable(&twi_sensors_instance);
}

void twi_read_register(uint8_t slave_address, uint8_t register_address, uint8_t *read_data, uint8_t data_length) {
	// Send register address
	nrf_drv_twi_tx(&twi_sensors_instance, slave_address, &register_address, sizeof(register_address), true);
	// Receive data
	nrf_drv_twi_rx(&twi_sensors_instance, slave_address, read_data, data_length, false);
}

void twi_write_register(uint8_t slave_address, uint8_t register_address, uint8_t *data, uint8_t data_length){
	uint8_t data_packet[data_length + 1];
	data_packet[0] = register_address;
	memcpy(data_packet+1,data, data_length);
	nrf_drv_twi_tx(&twi_sensors_instance, slave_address, data_packet, data_length +1, false);
}

Example of use 
 int8_t bno055_getTemp() {
 bno055_setPage(0);
 uint8_t t;
 bno055_readData(BNO055_TEMP, &t, 1);
 return t;
}
void bno055_setup() {
 bno055_reset();
 uint8_t id = 0;
 bno055_readData(BNO055_CHIP_ID, &id, 1);
 if (id != BNO055_ID) {
 printf("Can't find BNO055, id: 0x%02x. Please check your wiring.
", id);
 }
 bno055_setPage(0);
 uint8_t tmp = 0x0;
 bno055_writeData(BNO055_SYS_TRIGGER, &tmp);

 // Select BNO055 config mode
 bno055_setOperationModeConfig();
 bno055_delay(10);
}

void bno055_writeData(uint8_t reg, uint8_t *data) {
twi_write_register(BNO055_I2C_ADDR_LO,reg, data, sizeof(*data));
}

void bno055_readData(uint8_t reg, uint8_t *data, uint8_t len) {
twi_read_register(BNO055_I2C_ADDR_LO, reg, data, len);
} 
 Could someone indicate where the error is? 
 The problem may also be with the sensor itself, so could anyone suggest a simple read / write register test? 
 
 Regards