title: what is the use of SPL (secondary program loader)
body: <p>I am confused in clearing my concepts regarding these three questions</p>
  <ol>
  <li><p>why do we need a secondary program loader ?</p>
  </li>
  <li><p>in which memory it gets loaded and relocated ?</p>
  </li>
  <li><p>what is the difference between system internal memory and RAM ?</p>
  </li>
  </ol>
  <p>as far as I understand via reading links is .. <strong>SPL is required when the system internal memory can not hold the uboot completely so we need to initialize memory using a minimal piece of code called SPL</strong>. Does SPL actually relocate or it is only uboot which relocates itself?</p>