XO 1.5 B2


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XO-1.5 Laptop Beta test model 2 (B-Test 2), also known as B2.



The B2 prototypes are complete systems, externally appearing very similar to production XO-1s (CL1A). OLPC received a couple hundred of these in September, 2009. If you have a pre-production version of an XO-1.5, chances are it is a B2 version.

The B2 version, aside from problems starting up at cold temperatures, and an inability to maintain wireless across suspend/resume, function relatively well and are representative of XO-1.5 production laptops.


  • Identical externally to a production XO-1 with the single touchpad (CL1A).
  • A label in the battery compartment says B-TEST, and the serial number starts with SHC9370.
  • The motherboard has a daughtercard for the WLAN.
  • The motherboard has an internal SD slot
  • The motherboard is revision D


Software Support


XO-1.5 use Q3xxx firmware releases. These will not work on an XO-1.

Obtaining Firmware

B2 motherboards require a release equal to or later than Q3A10. We currently suggest using Q3A36.

Check the XO 1.5 EC dev changelog for information about the latest EC firmware (integrated into the above OFW releases).

Upgrading Firmware

You can upgrade to a different version of firmware by downloading a new firmware image, then:

  1. Place the firmware image (.rom) on a USB stick
  2. Ensure that you have both a somewhat charged battery and a DC power source
  3. Boot the laptop, pressing the escape key ('X' in upper left hand corner of keyboard) within a few seconds after boot to enter Open Firmware.
  4. Insert the USB stick containing the new firmware into a motherboard USB port
  5. Type:
flash u:\q3a15.rom

The flash command will fail if the laptop is not connected to external power or doesn't have a battery with reasonable charge inserted. There is a way to force the upgrade without meeting those requirements, but it is not recommended for regular use.


We currently provide a Linux build based on Fedora 11, which allows easy switching between a Sugar and a Gnome desktop.

Linux may be installed on the internal microSD card, or on an external SD (or microSD) card. Once installed on a microSD card, it may be used in either the internal socket or the external port (using an adapter).

Obtaining Linux

The latest Linux image for the XO-1.5 is available as the highest numbered os in http://build.laptop.org/. Download the img.gz file for installing from Linux, .zd file for installing from OFW.

You need os27 or later on a B2, as the DCON is not properly supported in earlier releases.

Installing from OFW

You will need the .zd version of the OS image. Download it, then:

  1. Place the image on a USB stick, and insert it into the XO-1.5 laptop's USB port.
  2. Boot the laptop, pressing the escape key ('X' in upper left hand corner of keyboard) within a few seconds after boot to enter Open Firmware.
  3. To install onto the internal SD card, type:
fs-update u:\os34.zd

To install an image onto the external SD card, you need to type:

devalias fsdisk /sd/disk@2:0
fs-update u:\os34.zd

Installing from Linux

On an XO-1

To install a Linux image onto an SD card inserted into an XO-1, you can run:

zcat os34.img.gz > /dev/mmcblk0
On an XO-1.5

This becomes a little more complicated on an XO-1.5, as there are two SD card slots and Linux doesn't name them consistently. If there are two SD cards found at boot time, the internal SD slot will be /dev/mmcblk0 and the external SD slot will be /dev/mmcblk1. Otherwise, the SD card found at boot will be named /dev/mmcblk0 and the second card inserted will be /dev/mmcblk1.

Assuming you boot from the internal SD card, the command to install a Linux image onto an SD card inserted in the external SD slot is:

zcat os34.img.gz > /dev/mmcblk1

If you have a Sandisk microSD card (provided in the internal SD slot of most B2 prototypes), you will probably want to write to it using this command instead (it greatly reduces the time required to write an image):

zcat os34.img.gz | dd obs=131072 of=/dev/mmcblk1

Hardware Limitations

The currently known hardware problems are:

Boot Problems at Cold temperatures

The B2 prototypes do not boot reliably at cold temperatures. This varies on a unit/unit basis, and was fixed by the C2 version. One way to quickly warm up a unit is to charge its battery.

Lid switch

The lid switch is flaky at best, completely non-operational (lid always closed) at worst. Tracked as #9911. This is fixed in versions of firmware later than Q3A25.

Power Draw

The B2 DC power input on B2s may reach 34W when running firmware earlier than Q3E15. With later firmware, the power draw is still 29W. There is an ECO which restores the laptop power to a 25W limit.

B2s also draw an inordinate amount of power (20mW) from the battery when turned off (and not plugged into a power source). This results in the battery life (with unit off) being rather short.


The B2 prototypes have shown a tendency to overheat. We are working on a more respectable solution than simply throttling back the processor. In the meantime, be aware that the laptop may begin to function erratically if it gets too hot. This usually manifests itself as problems reading/writing the internal SD card.

Versions of firmware later than q3a13 should automatically throttle the processor in case of overheating. Please let us know if you experience overheating problems running newer firmware.

The more permanent fix is to reduce power consumption in a few places and re-design the heat spreader to improve contact with the chips.

WLAN and suspend

Operation of the WLAN across a suspend/resume is not supported on an unmodified B2.

Test setup

There is an engineering change order (ECO) available to correct this.

DCON Interrupts

Interrupts from the DCON aren't detected reliably on B2 or earlier prototypes. There is an ECO available

EC/Host Interrupts

Interrupts from the EC to the host are filtered through ACPI. There is an ECO available which simplifies this, and will be applied to later versions.

Serial Port

The processor serial port situation on XO-1.5 is not optimal, as it shares pins with the camera interface. There is a connector (J4) located on the upper left hand side of the motherboard for +3.3V RS-232 connection (see the pinout and the connector/jumper locations), but its use must be enabled using a jumper.

To use the serial port you will have to short pins 1 and 3 on the SERIAL ENABLE jumper (JP1). This is located right behind the processor serial port (see the XO-1.5 B2 connector locations). Be aware that there is a test pad located next to the jumper block that erroneously looks like the pin 1 indicator. Pins 1 and 3 are the two pins closest to the memory chips.

There is no need to disconnect the camera in order to use the serial port. However, any use of the camera while the serial port is enabled will generate constant spurious serial data and is not recommended.

If the SERIAL_ENABLE jumper is set, the camera in-use LED will remain lit. This will not be fixed (Trac ticket #9385).


There are four LEDs located below the screen. From right to left, they are:

  • The power indicator -- if blinking, indicates that the unit is suspended.
  • The battery indicator -- used to indicate battery charge status.
  • The storage indicator "(*)" -- currently not supported by software, this indicator should show when the system is accessing the internal storage.
  • The WLAN indicator "!" -- This blinks when the WLAN is transferring packets.

Software Limitations

(Below list auto-sourced from F11_for_1.5/Known_Issues)

(obsolete reference, see release notes).


Supporting documentation for these boards are (in PDF):

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