I wonder why this creates HardFaultError rarely and randomly. Thanks

rxBuf is uint8_t array.

 // this creats HardFault sometimes:
 id = *(uint32_t *)&rxBuf[i];
//----------------------------------------------------
 // but this works OK forever:
 id = rxBuf[i + 3];
	id <<= 8;
	id += rxBuf[i + 2];
	id <<= 8;
	id += rxBuf[i + 1];
	id <<= 8;
	id += rxBuf[i + 0];