Firmware

From OLPC
Revision as of 07:29, 23 December 2014 by Quozl (talk | contribs)
Jump to navigation Jump to search
  This page is monitored by the OLPC team.

The firmware of the XO laptop is the software that runs before and during the operating system.

Updating - For Users

Updating the XO to a new operating system release updates the firmware, if required. Normally, users should update to the latest stable operating system release in order to update the firmware.

However, users may upgrade just the firmware to the latest signed release.

Updating - For Developers

Developers who have an unsecured laptop or a developer key have more options:

  • install any of the firmware releases below; choose one, download the .rom file, and then follow the Firmware/Install instructions.
  • alter the secure upgrade to use one of the firmware files below.

Note: avoid downgrading, as certain downgrades may brick your XO.

Brick Recovery

Updating using the methods above requires working firmware. If the firmware is not working, and the laptop is bricked, the options are:

Both these require electronics lab bench skills and service tooling. See Firmware/Recovery for more detail.

Firmware Releases

There is a subsection below for each laptop model, and a list of releases in each. Choose the correct laptop model. Do not mix firmware between models. Using the wrong firmware will be rejected by the flash command. Do not override this error, as the laptop may be harmed.

The first two letters of the firmware version serve as a laptop model. The following table shows how the prefix must be interpreted:

model start year prefix link
XO-4 2012 Q7 releases
XO-3 2011 Q5 releases
XO-1.75 2010 Q4 releases
XO-1.5 2009 Q3 releases
XO-1 2006 Q2 releases

The latest release is the first in the list.

XO-4

WARNING! XO-4 firmware will only work on an XO-4.

XO-3

WARNING! XO-3 Firmware will NOT work on an XO-1, XO-1.5 or XO-1.75.

XO-1.75

WARNING! XO-1.75 Firmware will NOT work on an XO-1 or an XO-1.5.

WARNING! XO-1.75 Firmware versions >= q4a10 will NOT work on A1 version boards.

WARNING! XO-1.75 Firmware versions >= q4b11 will NOT work on A2 version boards, and use on A3 requires a hardware modification.

XO-1.5

WARNING! XO-1.5 Firmware will NOT work on a XO-1.

XO-1

Do not downgrade from C series to B series

EC 1.5

EC 1.5 firmware is included in Open Firmware for XO-1.5.

EC 1.5 firmware development change log XO_1.5_EC_dev_changelog.

EC 1.75

EC 1.75 firmware is included in Open Firmware for XO-1.75.

EC 1.75 firmware and change log EC 1.75 Firmware.

EC 4

EC 4 firmware is included in Open Firmware for XO-4.

EC 4 firmware and change log EC 4.0 Firmware.

Technical Background

The firmware is in two parts:

  • EC Firmware, which runs on the embedded controller as soon as the battery is installed or external power is plugged in, and is responsible for managing the battery, charging, power switching, and indicator LEDs,
  • Open Firmware, which runs on the main processor when the power button is pressed, and is responsible for preparing that hardware and loading the operating system.

For XO-1 and XO-1.5, these two parts are bundled together as one .rom file. This firmware goes in the little 1 MB SPI FLASH that's used for booting, not the 1GB NAND flash (or 512MB in earlier prototypes) used for the OS image and user data. The SPI FLASH contains the Embedded controller ("EC") firmware, Open Firmware, and 2k Manufacturing Data. See Firmware SPI FLASH Map or its dia source file.

For XO-1.75, the .rom file contains Open Firmware and 2k Manufacturing Data and is stored in one SPI FLASH chip attached to the SoC. The Embedded controller ("EC") firmware is stored in another SPI FLASH chip attached to the EC. Therefore EC firmware is not bundled with Open Firmware.

See also

Retrieved from "http://wiki.laptop.org/mediawiki/index.php?title=Firmware&oldid=297060"