Bering-uClibc 5.x - Developer Guide - Appendices - Hardware-Specific Guides

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Revision as of 20:28, 30 June 2012 by Davidmbrooke (Talk | contribs) (Boot Disk Layout: Updated details of the boot-partition files)

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Boot Disk Layout

The Raspberry Pi must boot from its SD card and some vital files must be present in the root directory of the boot partition.

The latest versions of these files can be downloaded from the raspberrypi/firmware page on GitHub.

The first disk partition on the SD card must be formatted as a VFAT filesystem. It works OK if the partition type is 0xb (W95 FAT32) This partition does not have to to be marked as "bootable".

The critical files are:

  • A file called start.elf which contains the GPU binary driver
  • A file called bootcode.bin which contains the second stage bootloader
  • A file called loader.bin which contains the third stage bootloader
  • A file called kernel.img which contains the Linux kernel
    • This is a standard (uncompressed) Linux kernel Image file

Some additional files are optional but are referenced if present:

  • A text file called config.txt
The Raspberry Pi config.txt file is read by the GPU before the ARM core is initialised. It can be used to set various system configuration parameters.
  • A text file called cmdline.txt containing the kernel command line

It seems customary to put the files relating to a particular Linux distribution on a second disk partition. We probably therefore need a second VFAT disk partition for leaf.cfg, all the .lrp Package files etc.

Note that the Raspberry Pi references the first disk partition as /dev/mmcblk0p1 and the second disk partition as /dev/mmcblk0p2.

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