Installing to NAND

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Revision as of 21:23, 25 August 2006 by Cjb (talk | contribs)
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Overview

This page describes how to write a filesystem to the board's internal NAND flash and boot from it using LinuxBIOS.

Requirements

You should have a working install of one of the OLPC Build images, build 78 or higher, and a copy of the corresponding jffs2.img for that build available. (For example, on another USB key.)

Procedure

After the board has booted, hit ctrl+alt+F1 to get to a login prompt, and login as root. Then:

  modprobe mtdchar
  flash_eraseall -j /dev/mtd0
  nandwrite -p /dev/mtd0 /path/to/olpc-development-rpm-jffs2.img

We intend to provide a mechanism to let the jffs2 img be streamed to nandwrite over the network, for people with only one USB key; this isn't working currently, though.

It is normal to see bad block errors during both the flash_eraseall and nandwrite steps. When the nandwrite has finished you can reboot, and LinuxBIOS will boot from the NAND flash. A delay of around 80 seconds on boot is normal; the filesystem we wrote to the NAND was compressed, and is uncompressed on boot.

Troubleshooting

  • flash_eraseall: /dev/mtd0: No such file or directory

This is seen when modprobe mtdchar wasn't performed.

  • I see a hang after "NOTICE: Booting default"

This is normal, and should last for around 80 seconds. The filesystem on the NAND flash is being uncompressed.

  • JFFS2 warning: (1381) jffs2_sum_write sumnode: Not enough space for summary, padsize = -793

This warning is harmless.