Upgrading to LinuxBIOS: Difference between revisions

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===The procedure===
===The procedure===


You need a USB key, an OLPC devel board with a powered USB 2.0 hub
You need a USB key, an OLPC devel board with a powered USB 2.0 hub and a USB keyboard ''(important)'', and a Linux-based host system.
and a USB keyboard ''(important)'', and a Linux-based host system.
([[#Hardware Requirements - Details|More hardware details...]])
([[#Hardware Requirements - Details|More hardware details...]])
([[#Using Windows as a Host System|Using Windows as a Host System...]])
([[#Using Windows as a Host System|Using Windows as a Host System...]])
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Get http://dev.laptop.org/~wmb/spi_flash_linuxbios-20060820.dd
Get http://dev.laptop.org/~wmb/spi_flash_linuxbios-20060820.dd
(md5sum: 3d2d8728c4fa1554ff15e914db80dd7c ) onto the host system. '''(Source code location is TBD.)'''
(md5sum: 3d2d8728c4fa1554ff15e914db80dd7c ) onto the host system. '''(Source code location is TBD.)'''

The source tarball(s) for the packages in the ROM image and the image BOM is available from http://dev.laptop.org/www/gpl.


Plug your USB key into the host system, verify that /dev/sda is its
Plug your USB key into the host system, verify that /dev/sda is its

Revision as of 00:07, 22 August 2006

Important: This procedure is currently being vetted. Unless you are one of the designated testers, please ignore this page until this message is removed (hopefully within the next day or so).


Purpose

This procedure installs LinuxBIOS in the SPI FLASH of an OLPC development board, replacing the factory-installed Insyde BIOS. Insyde BIOS expires on Aug. 26, 2006, so the OLPC team hopes to cut over to LinuxBIOS soon.

Warnings

  • This is a one-way procedure. Once you have installed LinuxBIOS and rebooted, going back to Insyde BIOS requires other tools and procedures.
  • LinuxBIOS is not compatible with Insyde BIOS. After LinuxBIOS is installed, old OLPC software installations that used to work under Insyde BIOS may no longer boot.

The procedure

You need a USB key, an OLPC devel board with a powered USB 2.0 hub and a USB keyboard (important), and a Linux-based host system. (More hardware details...) (Using Windows as a Host System...)

Get http://dev.laptop.org/~wmb/spi_flash_linuxbios-20060820.dd (md5sum: 3d2d8728c4fa1554ff15e914db80dd7c ) onto the host system. (Source code location is TBD.)

The source tarball(s) for the packages in the ROM image and the image BOM is available from http://dev.laptop.org/www/gpl.

Plug your USB key into the host system, verify that /dev/sda is its correct name (Alternative names for /dev/sda...) and type:

$ dd bs=5M if=/dev/sda of=oldkey.img
$ dd bs=5M if=linuxbios.img of=/dev/sda

Move the USB key to the OLPC board (connect it via the powered USB 2.0 hub).

Boot the OLPC board (Boot sequence details...)

When it finishes booting, there will be a "$" shell prompt hidden in the midst of some USB probing messages.

On the OLPC USB keyboard, type:

$ flashlb

(Details of what flashlb does...)

If something goes wrong (shouldn't happen :-), see #Disaster Recovery.

If all goes well (i.e. the verification step succeeds), you can upgrade some more OLPB boards by repeating the boot/flashlb steps.

After you have upgraded all your OLPC boards, you can restore the previous contents of your USB key if you wish. Plug the USB key back into the host system and type:

$ dd bs=5M if=oldkey.img of=/dev/sda

This is the end of the procedure. The sections below contain additional information that may be useful if you have problems or are just curious.

Hardware Requirements - Details

  • An OLPC development board - this is the machine whose SPI FLASH you will update.
  • A powered USB 2.0 hub attached to the OLPC board.
  • A USB keyboard attached to that powered hub. (Don't use a PS/2 keyboard; it won't work right with this procedure because of a hardware interaction between the PS/2 and SPI programming circuits.)
  • A USB FLASH key drive. Any size will do, since the software image is only 5 MB. I tested with a SanDisk Cruzer Mini 1.0GB device. The procedure preserves and restores the USB key's existing contents so you can use a USB key that already has stuff on it.
  • A working Linux-based "host system" to copy the software image to a USB key (or see #Using Windows as a Host system).
  • If you have an Uninterruptible Power Supply, it's a good idea to power the OLPC board from it. A power failure during FLASH programming is difficult to recover from.

Linux USB drive device names

On many Linux systems, USB mass storage devices (e.g. USB key drives) have device names like /dev/sda, /dev/sdb, etc. Those are the same names that are used for SCSI disks, because USB mass storage devices use SCSI-like commands at one level of their software protocol.

In the common case where there is only one USB key drive and no "real" SCSI hard disks, the device name will be /dev/sda. If there are multiple USB mass storage devices or some SCSI hard disks, the USB key might be /dev/sda, /dev/sdb, /dev/sdc, etc. Make sure that you find the right one, because you don't want to overwrite the wrong drive.

On some Linux systems, USB mass storage devices have names like /dev/uba, /dev/ubb, etc. ("ub" instead of "sd").

Boot sequence details

This section describes what you should see while the reflashing software is booting under Insyde BIOS.

A few seconds after power on, the white Insyde BIOS banner screen will appear. A little later, the top of that screen will show the results of USB probing. Those results should include your USB key.

Then the screen will switch to white text on a black background. Eventually it will boot GRUB (the intermediate bootloader). After a brief timeout, GRUB will then start Linux. When Linux takes control of the screen, the font size will decrease and you'll see a lot of Linux startup messages.

New startup message will stop appearing after a few seconds. The last few lines on the screen will be messages about "/dev/sda" from the USB subsystem. The "$" prompt from the shell will already be on the screen, but it's hard to find because there are several USB messages after it.

If you want to get a fresh prompt, just type the Enter key.

flashlb details

The steps that occurs during the execution of "flashlb" are as follows. It should be clear from the screen messages which steps are happening.

  1. Make a backup copy of the SPI FLASH in /insyde.rom (unless /insyde.rom already exists)
  2. Erase the SPI FLASH
  3. Write the contents of /linuxbios.rom to the SPI FLASH
  4. Verify that the newly-written data matches the file

Disaster Recovery

If the reflashing process fails, Don't power off the OLPC board just yet. Here are some things you can try that might be helpful. These are just suggestions, because I've never seen any failures - recovery procedures for hypothetical failures are inherently speculative.

Retrying the write command

You can retry the command that writes the SPI FLASH, i.e.

$ flashlb

Retrying might conceivably be of some use if the failure was transient.

Re-executing flashlb won't overwrite the /insyde.rom backup file that was created on the first try, since the program only creates a backup if no such file exists.

Restoring Insyde BIOS

You might be able to restore the Insyde BIOS with

$ restore

This only works if you haven't powered off or otherwise reset the OLPC board since you loaded LinuxBIOS into FLASH. The reason is because LinuxBIOS cannot boot the software that we use in this procedure, which is set up to be booted by Insyde BIOS.

If something went wrong with the flashlb process, it's possible - perhaps even likely that the same problem might also affect "restore". So don't expect miracles from "restore"; it is provided "just in case it helps".

("restore" was helpful in the testing of this procedure, allowing me to test the procedure several times before committing to the "one way" nature of the upgrade.)

Using Windows as a Host System

http://www.chrysocome.net/dd has a version of the "dd" command that runs under Windows. The command line arguments are compatible with the Linux version, but you have to use the Windows form of the USB device name (not /dev/sda). The Windows "dd" has a "--list" command to help you discover the right device name.