Documentation/powerpc/zImage_layout.txt

   1           Information about the Linux/PPC kernel images
   2 =====================================================================
   3
   4 Please mail me (Cort Dougan, cort@fsmlabs.com) if you have questions,
   5 comments or corrections.
   6
   7 This document is meant to answer several questions I've had about how
   8 the PReP system boots and how Linux/PPC interacts with that mechanism.
   9 It would be nice if we could have information on how other architectures
  10 boot here as well.  If you have anything to contribute, please
  11 let me know.
  12
  13
  14 1. PReP boot file
  15
  16   This is the file necessary to boot PReP systems from floppy or
  17   hard drive.  The firmware reads the PReP partition table entry
  18   and will load the image accordingly.
  19
  20   To boot the zImage, copy it onto a floppy with dd if=zImage of=/dev/fd0h1440
  21   or onto a PReP hard drive partition with dd if=zImage of=/dev/sda4
  22   assuming you've created a PReP partition (type 0x41) with fdisk on
  23   /dev/sda4.
  24
  25   The layout of the image format is:
  26
  27   0x0     +------------+
  28           |            | PReP partition table entry
  29           |            |
  30   0x400   +------------+
  31           |            | Bootstrap program code + data
  32           |            |
  33           |            |
  34           +------------+
  35           |            | compressed kernel, elf header removed
  36           +------------+
  37           |            | initrd (if loaded)
  38           +------------+
  39           |            | Elf section table for bootstrap program
  40           +------------+
  41
  42
  43 2. MBX boot file
  44
  45   The MBX boards can load an elf image, and relocate it to the
  46   proper location in memory - it copies the image to the location it was
  47   linked at.