Instead of editing the .hex file as suggested in the README.TXT we can use this approach:
$ dd if=/dev/zero of=pad2mb.bin bs=1024 count=2048
$ cat nuttx.bin pad2mb.bin > nuttxpad.bin
$ dd if=nuttxpad.bin of=nuttxpad2mb.bin bs=1024 count=2048
$ cat nuttxpad2mb.bin nuttx_user.bin > nuttxfinal.bin
