elftosb —
generate secure boot images for Freescale processors
  
    | elftosb | [ -?,--help]
      [-C,--componentversion] [-c,--commandfile] [-D,--defineconst] [-d,--debug]
      [-f,--chip-familyfamily] [-k,--keyfile] [-O,--optionoption] [-o,--outputfile] [-P,--productversion] [-p,--search-pathpath] [-q,--quiet]
      [-V,--verbose]
      [-v,--version]
      [-z,--zero-key]
      files... | 
The elftosb program is used to create a digitaly signed
  secure boot (sb) file. This sb file can be booted by the first stage boot
  loader found in Freescale i.MX23 and i.MX28 application processors. One or
  several ELF files and optionally a key are taken as input and processed under
  the control of a command file to generate the sb file.
Copyright (c) 2004-2010 Freescale Semiconductor, Inc.
The elftosb program and its command file syntax are
  poorly documented.