The CB 550 (Picture 7.1) does have the jumper on the motherboard which is the read/write protector. This connector must be jumped and the developer mode switch on the right side in the on position, the switch is towards the back of the device, if it’s towards the front it's in the off position. (Picture 7.2, 7.3) before you put the CB 550 into developer mode and change the SN. If you do not, the SN will not save, show and error message, and also corrupt the OS. If this happens reinstall the OS and make sure the jumper is jumped and the developer switch is in the correct position.

Picture 7.1

Get to developer mode: Chromebook XE550C22

Make sure you have placed the jumper in the correct location before moving on to the next steps! Picture 7.1 on the previous page shows the location of the jumper connector.

Developer switch: Picture 7.2, 7.3

The developer switch enables the command line shell. The switch is behind a little door on the right-hand side of the chromebook. To enable the developer switch you open the door, use something pointy to move the switch towards the back of the device, and reboot. Note: be gentle! Some people have reported that the developer switch breaks easily.

The first time you reboot after turning the developer switch on, your chromebook will:

• • Show a scary warning that its software cannot be trusted, since a command line shell is enabled.

    • Press Ctrl + D

    • This process will erase all personal data on the "stateful partition" (i.e., user accounts and settings - no worries, though, since all data is in the cloud!).

    • Make you wait between 5 and 10 minutes while it erases the data.

The erase and wait steps only happen when you first enable the developer switch, to help prevent someone from quickly reimaging your device while you're away from the keyboard. Successive boots will:

• • Show the same scary warning

    • Press Ctrl + D

  • Continue to boot only Google-signed images, and only from the SSD.

To get to the command prompt:

• • Wait until the device boots to the Chrome start screen.

    • Press Ctrl + Alt + → (Ctrl-Alt-F2)

Once in the command prompt continue to the next page, if not in a command prompt retry the above steps.

Once in developer mode: Chromebook XE550C22

Type as shown below, if it’s Capital leave it Capital, if its lowercase leave it lowercase. Spaces are important make sure if there is a space you type it in the terminal.

• • Type: chronos

    • Press Enter

  • Type: sudo su

    • Space after “sudo”.

    • Press Enter

  • Type: vpd -l (lowercase L)

    • Space after “vpd”.

    • Once you type vpd -l, this will display the current motherboards information including the motherboards current serial number.

  • Press Enter

• Type: vpd -s “serial_number”=”0000000000”

  • Replace the 000’s with the Device Serial number from the original device

  • Space after “vpd”, Space after “-s”.

  • Make sure the serial number is CAPITAL letters.

  • Press Enter

• Type: vpd -d “Product_S/N”

  • Space after “vpd”, Space after “-d”.

  • Press Enter

• If flashromPartialWrite() error displays go back to where the jumper is placed and make sure it is securely in. Re-seat it to make sure.

  • Type: dump_vpd_log --force

    • Space after “dump_vpd_log”.

    • Press Enter

  • Type: dump_vpd_log --full --stdout

    • Space after “dump_vpd_log”, Space after “--full”.

    • Press Enter

  • To close the command line session, type EXIT to close shell and EXIT to close the terminal.

    • • Put the developer switch back into the off position (button towards the front of the laptop)

      • Remove the jumper.

      • Re-screw the bottom plate back onto the device.

• Leave the device in developer mode once the repair is completed, so that the QC Team can Verify the SN Change.