Save struct to flash memory

Question

Hello guys. 
 I am able to save an array to flash memory unfortunately I can not save a struct in flash. I am referring to this question Save struct to flash . However I am not able to save it using that example. Where I am doing a mistake in here? 
 This is my structure: 
 __align(4) struct 
 {
 uint8_t sleep_time_min;
 uint8_t advertise_time_sec;	
 }default_commands;
 
 This is pstorage initialization function: 
 void my_pstorage_init(void)
 
 {
 uint32_t err_code;
 
 pstorage_module_param_t param;
 param.block_size = 40; //Select block size of 32 bytes
 param.block_count = 1; //Select 2 blocks, total of 64 bytes
 param.cb = my_pstorage_cb_handler; //Set the pstorage callback handler
 
 err_code = pstorage_init();
 APP_ERROR_CHECK(err_code);
 err_code = pstorage_register(&param, &base_handle);
 APP_ERROR_CHECK(err_code);
 
 }
 
 This is clearing function: 
 void my_pstorage_clear(void)
 {
 pstorage_handle_t block_handle;
 uint8_t index;
 uint32_t err_code;
 
 index = 0; //we will write to the second block
 err_code = pstorage_block_identifier_get(&base_handle, index,&block_handle);
 APP_ERROR_CHECK(err_code);
 
 err_code = pstorage_clear(&block_handle,40); 
 APP_ERROR_CHECK(err_code);
 pstorage_wait_handle = block_handle.block_id; //Specify which pstorage handle to wait for 
 pstorage_wait_flag = 1; //Set the wait flag. Cleared in the my_pstorage_cb_handler
 while(pstorage_wait_flag) { power_manage(); } //Sleep until clear operation is finished.	
 
 
 }
 
 Write function: 
 void my_pstorage_write(void)
 {
 pstorage_handle_t block_handle;
 uint8_t index;
 uint32_t err_code;
 
 index = 0; //we will write to the first block
 //Store data to blocks or just block. Wait for the last store operation to finish before reading out the data.
 err_code = pstorage_block_identifier_get(&base_handle, index,&block_handle); 
 APP_ERROR_CHECK(err_code);
 
 err_code = pstorage_store(&block_handle, (uint8_t*)&default_commands,sizeof(default_commands),0); //Write to flash, only one block is allowed for each pstorage_store command
 APP_ERROR_CHECK(err_code);
 pstorage_wait_handle = block_handle.block_id; //Specify which pstorage handle to wait for
 pstorage_wait_flag = 1; //Set the wait flag. Cleared in the my_pstorage_cb_handler
 while(pstorage_wait_flag) { power_manage(); } //Sleep until store operation is finished.
 }
 
 My main function: 
 int main(void)
 {

	default_commands.sleep_time_min = 1;
	default_commands.advertise_time_sec = 30;
	
 my_pstorage_init();
	my_pstorage_clear();
	
	my_pstorage_write();
	my_pstorage_read();
	my_pstorage_clear();
 }
 
 EDIT______________________________________________________________
So the problem is that microcontroler becomes unresponsive in this case PSTORAGE_STORE_OP_CODE when reaches line retval = sd_flash_write(); 
 case PSTORAGE_STORE_OP_CODE:
 {
 uint32_t size;
 uint32_t offset;
 uint8_t * p_data_addr = p_cmd->p_data_addr;

 offset = (m_round_val * SOC_MAX_WRITE_SIZE);
 size = p_cmd->size - offset;
 p_data_addr += offset;
 storage_addr += (p_cmd->offset + offset);

 if (size < SOC_MAX_WRITE_SIZE)
 {
 retval = sd_flash_write(((uint32_t *)storage_addr),
 (uint32_t *)p_data_addr,
 size / sizeof(uint32_t));
 }