ROM non-XIP image

In this scenario, the image doesn't execute in place:

Here are the steps required in the IPL:

checksum (image_paddr, startup_size)
checksum (image_paddr + startup_size, stored_size - startup_size)
copy (image_paddr, ram_paddr, startup_size)
jump (startup_vaddr)

And here's the step required in the startup:

copy (ram_paddr + startup_size, image_paddr + startup_size,
      stored_size - startup_size)