Saving byte array in PROGMEM instead of SRAM
See Putting constant data into program memory (PROGMEM) for tips about putting stuff into PROGMEM. However personally I wouldn't get too excited about saving 6 bytes.



Example code:

Declare data globally:

const byte mac [6] PROGMEM = { 0x90, 0xA2, 0xDA, 0x0F, 0xE1, 0x85 };


Get a copy for use into a temporary variable:

  char foo [6];
  memcpy_P (foo, mac, sizeof foo);