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HowTo [ID# 195094]  +/-

A developer key is a file containing cryptographic information tied to a specific XO laptop.

What you can do with a developer key

If you don't have a developer key, and your laptop has firmware security enabled, it will not let you do anything except boot an OLPC-signed operating system, and use the OLPC-provided software. If you insert a USB flash drive or SD card, the boot firmware will only boot from it if the files are tested and cryptographically signed by OLPC.

If the boot firmware sees a developer key in /security/develop.sig, it makes the XO laptop work just like any ordinary PC-style laptop:

• it will let you interrupt the boot process and enter commands
• it will try to boot and run any program you supply to it, such as a Fedora or Debian Linux system, no matter whether the OLPC organization has tested, approved, or signed it.

The laptop also works this way if its firmware security is permanently disabled.

OLPC produces many unsigned operating system images for development and testing, which will only work in your laptop if you have a developer key. Also, if your laptop refuses to boot because the clock is set wrong, or complains about an unsigned kernel, getting a developer key is a critical part of diagnosing and/or fixing the trouble.

This firmware security is part of the BitFrost security system, and is used to ensure that unless the user has specifically opted out, their basic operating software remains unmodified. This feature is contentious (see discussion). Frequently referred to as "Tivoization", this kind of deliberate manufacturer's restriction on ordinary people's use of their hardware is a form of "Digital Rights Management" or DRM. Bypassing the XO firmware security (jailbreaking) is relatively easy because the OLPC organization explicitly allows it, via the process described in this web page.

All production XO laptops have had firmware security enabled. This includes laptops obtained through the Give One, Get One program.

The firmware will look for a developer key on your laptop's internal flash memory; on any USB flash drive that's plugged in; and on any SD card that's plugged in. It needs to be in /security. (See Firmware security for the gory details.)

With a developer key, whenever the laptop boots, the firmware will give you the option to press the Escape key (at the upper left, marked ) and get an ok prompt, which lets you enter commands in Forth. If you don't press the Escape key, after a short countdown the firmware continues booting the operating system.

• This is the insecure boot process, and it will boot into any image you install on the xo.
• Rather than drawing pretty pictures on the screen, lots of text messages will be displayed, and will eventually scroll up the screen. This is normal, and can be useful for diagnosing problems in your laptop.
• The insecure boot process does not automatically upgrade firmware; you will be responsible for updating your firmware yourself.

Getting a developer key for your running XO laptop

1. On your XO, open the Browse activity.
2. There's a "Developer key request" web page on the XO to apply for a key. There are several ways to navigate to this page:
   • In all builds, you can type file:///home/.devkey.html in the browse location field to get to the request page.
   • In recent builds (including 8.2.0), "Get a developer key" is at the bottom of the Browse start page.
   • In older builds (8.1, 703 and higher), click "activities" in the OLPC Library left-hand navigation, click on the sub-menu "find activities", and at the bottom of the page that displays is the "apply for developer key" link. Also, under "books" in the OLPC Library, click on the sub-menu "explore your xo", click "troubleshooting", and under "How do I get a developer key for my laptop" is a link to "submit this form"
   • In still older builds (7.1, 650, 653, and 656), click on the Library link "other" and then on "about your xo". Click on the "apply for a developer key" link at the very bottom of the page. (You can press the 'check mark' (✓) game key to quickly get to the bottom of the page.)
3. Follow the directions to apply for a developer key; it should be created in a day or two.
4. Go back to the request page when your key is ready, and follow the instructions to download your key to your XO.
   • Once your key has been created, you can return to this page at any time on your XO to re-download it; there will be no further creation delay.
5. Reboot your XO.

Tip: if the typeface is too difficult to read easily, you can use Browse's Zoom options (in the View menu) to make it larger. Alternatively, you can copy the text and paste it into the Write activity, where you can resize it.

After you get a developer key

Make back up copies!

However you get a key, please make a copy of it on some other computer, one that gets backed up regularly, in case this one is lost. Also, you should copy your developer key to /security/develop.sig on a USB flash drive, if you have one.

Disable the security system

Once you have a developer key and have booted your system using it, it is possible to permanently disable the firmware security system, even if your XO's developer key goes away. If you forget to do this, and you usually run ordinary free software distributions like Debian, Ubuntu, or Fedora on your XO, your XO will at some point refuse to boot.

To will permanently turn off firmware security on your laptop:

1. Reboot the XO
2. Press the Esc key during boot to get to the 'ok' prompt.
3. Type 'disable-security' at the 'ok' prompt and press enter

If disable-security says "Restarting to enable SPI flash writing. Try again after the system restarts.", you'll need to start over with the Esc key again as above. If disable-security says "No wp key", it means that security is already disabled.

• When security is disabled, you can still re-enable it for a single boot by pressing the X gamepad key while turning the power on. This is useful to do firmware upgrades from signed builds. It can also help to test secure boot on release candidates.
• You can reverse the 'disable-security' command by entering 'enable-security' at the 'ok' prompt.
• You can see the raw manufacturing data where the disable-security setting is stored by typing ".mfg-data". See Manufacturing data for details.

If you wipe out your developer key

If you reflash your XO you will remove /security/develop.sig. One way this can happen is if you ever do a fresh install of an operating system image using the clean-install procedure (rather than olpc-update). If you haven't disabled security and the OS image that overwrote flash is unsigned, then your laptop won't boot. But you have several options:

• Revert to a previous OS image. Try pressing the 'O' (circle) gamepad key while booting. That will attempt to boot a previous version of the OS, and if it was signed it will succeed.
• Reflash again with a signed OS image.
• Insert a USB flash drive or SD card with your developer key on it in /security/develop.sig (this is why you should always be sure to backup develop.sig), which will allow booting of the unsigned OS image and/or let you get to the 'ok' prompt to disable security.

Once boot completes you can restore your developer key back to NAND flash by typing in a terminal something like

 cp -pi /media/MY_USB_NAME/security/develop.sig /security

or you can re-visit the "Developer key request" form and re-download your developer key. But you would be better off if you immediately disabled security, as described above; that never expires, unlike developer keys in NAND flash that often get overwritten.

Getting a developer key without WiFi

If you have some network access, you can:

• use a USB-to-wired ethernet adapter to get your XO on the net, then follow the above instructions.
• copy the file /home/.devkey.html from the XO to another (network-connected) machine, and perform the process from that machine. Entering the following command in the Terminal activity will copy it to any USB devices connected:
  • cp -p /home/.devkey.html /media/*/devkey.html

Getting a developer key without network

Via snail mail

You can submit a written request via snail mail to:

One Laptop per Child
P.O. Box 425087

Cambridge, MA 02142

Your key will be mailed back to you.

If the machine won't boot

Revert to a previous OS image

First, try booting with the 'O' (circle) gamepad key held down. That will attempt to boot a previous version of the OS, after which you can use one of the options above.

Generate a laptops.dat file

See the USB stick method directly below. You can collect a laptops.dat file with the UUID information of your machine, or of many machines, with a single stick. This method will sometimes work when simply submitting the serial number to OLPC doesn't. This is because the laptops.dat file contains additional information about the system (the system date and UUID) which must be correct but is looked up or assumed when only a serial number is submitted.

Getting devkey data via USB stick

This requires a USB memory stick, and manual assistance from someone at OLPC. The memory stick must be set up to work as a collection stick by adding code that at boot time copies information from the XO to itself. After using it, you should send the resulting file to OLPC.

• Set up a collection stick
• Plug the stick it into your laptop and power it on
• It will display a pretty "XO" screen and then a short message like "SHFxxxxxxxx nnnnnnnnnnnnnnn; Laptop data recorded successfully". After a few seconds it will power itself off or indicate it is done.
• Remove the USB stick and move the file to a different computer
• Open laptops.dat in a text editor and take a look.
• Enter your Serial Number (EG. CSNxxxxxxxx, SHFxxxxxxxx, or SHCxxxxxxxx) and UUID (nnnnnnnn-nnnn-nnnn-nnnn-nnnnnnnnnnnn) from laptops.dat into https://activation.laptop.org/devkey/post/
• Return to https://activation.laptop.org/devkey/post/ 24hrs later and your Developer Key should be ready!
• Problems? Email the laptops.dat file to help@laptop.org . Please describe your problem, including the serial number (printed inside your battery compartment, visible when you remove the battery), and attach the resulting laptops.dat file.

Setting up a collection stick

1. Download Actos.zip and Runos.zip (its source code in Forth, if you're interested, is at http://dev.laptop.org/git?p=users/cscott/actkey; it will only run if it's put into a signed zip file.)
2. Put these files into the /boot/ directory on a FAT-formatted or FAT32-formatted USB flash drive.
   • Most USB flash drives use FAT or FAT32 when you buy them (except "U2" memory sticks which probably won't work; they contain their own ugly DRM stuff).
3. Your USB flash drive should contain these files (and nothing else in the boot directory):

   boot/

   boot/Actos.zip

   boot/Runos.zip

4. If there is an old laptops.dat file on the USB flash drive from an earlier collection of laptops, you can delete it. However, see below : if you are gathering data from a number of laptops, do not delete the file in between XOs. The USB flash drive can have any other files on it that you like.

Getting devkey data for many XOs at once

For each laptop that you want to get a Developer Key for:

1. Repeat the above process, inserting your collection stick and powering on the laptop, for each XO in turn.
   • This will combine metadata for each laptop into one laptops.dat file, so do not delete the laptops.dat file in between.
2. Enter all Serial Numbers (EG. CSNxxxxxxxx, SHFxxxxxxxx, or SHCxxxxxxxx) and UUID's (nnnnnnnn-nnnn-nnnn-nnnn-nnnnnnnnnnnn) from laptops.dat into self-service site https://activation.laptop.org/devkey/post/ as described above.
3. If problems, email the resulting laptops.dat file to help@laptop.org, indicating the # of laptops you need keys for, and explaining extenuating circumstances.

Then wait for OLPC to send you your Developer key(s) and/or Activation key(s).

What to do when you receive your activation or developer keys

NB: OLPC may also send you other files to put on the USB flash drive, to help to patch or circumvent whatever problem is preventing your laptop from booting properly.

1. You can use the same USB flash drive that you used as collector stick.
2. You'll receive one or two files from OLPC. Extract the file or files using your email program.
   • If you receive a lease.sig file, it's your activation key. (G1G1 laptops don't need one.) Copy the file into the root directory of your USB flash drive.
3. Make a directory called security/ in the root directory of your USB flash drive, and copy the developer key develop.sig file into it.
4. You should now have these files on your key:

   lease.sig (if received)

   security/

   security/develop.sig

5. With the laptop powered off, insert the key into a USB port and power it on.

   If the laptop wasn't previously activated, it will now boot.

   Any activation key provided will be copied to /security/lease.sig on the XO. Keep the activation key around (or copy it to your school server) in case you later need to reflash the XO.

6. If you have a developer key, you should see a textual prompt, which you will see within the first few seconds of booting (along with a short countdown to give you time to hit the Escape key). This is your indication that the developer key has been found.
   • To permanently disable secure booting, press Escape and type "disable-security", then power cycle and repeat that command. (see Disabling Security, above.)
7. The developer key is not automatically copied to your laptop's internal flash memory. You can do that by copying security/develop.sig from the USB flash drive into /security/develop.sig on the XO. You'll need to be root in a Terminal activity to do that.

Remove the USB key as usual -- via the Journal or after you are at an "ok" prompt in the boot firmware.

If you requested keys for more than one laptop, you can use the same process and the same USB key for each laptop.

See also

• OLPC on free/open source software
• olpc-update
• Updates
• Software update

Note: the Developer key page generated by the OLPC Activation Service (in response to a developer key request from the XO) links to this page.