Putting the images together

Note the following about the os1.build file:

• The startup code is doing the copy of flash from 0xFE300000 to RAM at 0x600000. This new startup was called startup-mgt5200-dual.

  In order to make this copy, edit the BSP's bsp-startup-mgt5200/mgt5200/main.c and modify the main() function:

  ...
  
  add_typed_string(_CS_MACHINE, "MGT5200");
  
  /* Load the bootstrap executables in the image filesystem and
     initialize various syspage pointers. This must be the *last*
     initialization done before transferring to the next program. */
  
  init_system_private();
  
  /* At this point, copy the second image to RAM:
      - The source will be 0xFE300000  (physical flash address)
      - The destination will be 0x600000  (physical RAM location)
  
          Make sure the destination is the same physical address XXXXXX that
          is specified in the 'startup-mgt5200 -r XXXXXX,YYYYYY,Z' in the
          buildfile.
      - The size to copy is 0x50000. The size to copy must be at least as 
        large as the os2.ifs file. It is recommended to erase the flash area
        for os2.ifs so that any extra bytes at the end are zero.
      
     This copy must be done after the init_system_private() call. */
  
  copy_memory( 0xFE300000, 0x600000, 0x50000 ); 
  
  /* Dump the system page if verbose level 3 (-vvv) */
  if (debug_flag > 2)
  {
      print_syspage();
  }
  
  return 0;
  

• By default, the entire contents of SDRAM are zeroed when the board is initialized. If you don't want this to happen, then you will need to modify the startup code.
• When startup-mgt5200-dual is given the -r option to reserve system memory, the third argument is a flag that indicates if memory will be cleared. If you are warm-booting your CPU with memory still active, then you won't want to clear the memory. Set the flag to 0 to clear, or 1 to not clear.

It's possible to mount multiple image filesystems at the same mountpoint. For example:

mount -tifs -o offset=0x600000,size=0x24000 /dev/mem /
mount -tifs -o offset=0xa00000,size=0x31000 /dev/mem /

This mounts two additional images at the root (/) mountpoint. QNX Neutrino supports union filesystems. If there are duplicate paths to the same file, then the last image to mount will be the one that's used.