uint64_t value creating from 8 bytes

Projects Programming
2

That is not in reverse. That is some kind of magical mixing with unknown conditions.
If you need '14BDB6571', then you need: 00 00 00 01 4B DB 65 71. So it is in reverse order after all ?

Is the 0x71 the first received byte ?
To do it in reverse, you could use this:

byte buffer[8] = { 0x71, 0x65, 0xDB, 0x4B, 0x01, 0x00, 0x00, 0x00);
uint64_t result = 0;
for( int i=7; i>=0; i--)
{
  result <<= 8;
  result |= (uint64_t) buffer[i];
}

For which Arduino board ?
I think that the Arduino Uno can not print it. Perhaps the Arduino Due or Arduino Zero can convert the uint64_t with sprintf().