r2d2b2g: an experimental prototype Firefox OS test environment

Developers building apps for Firefox OS should be able to test them without having to deploy them to actual devices. I looked into the state of the art recently and found that the existing desktop test environments, like B2G Desktop, the B2G Emulators, and Firefox’s Responsive Design View, are either difficult to configure or significantly different from Firefox OS on a phone.

Firefox add-ons provide one of the simplest software installation and update experiences. And B2G Desktop is a lot like a phone. So I decided to experiment with distributing B2G Desktop via an add-on. And the result is r2d2b2g, an experimental prototype test environment for Firefox OS.

How It Works

r2d2b2g bundles B2G Desktop with Firefox menu items for accessing that test environment and installing an app into it. With r2d2b2g, starting B2G Desktop is as simple as selecting Tools > B2G Desktop:

B2G Desktop Menu Item

To install an app into B2G Desktop, navigate to it in Firefox, then select Tools > Install Page as App:

Install Page As App Menu Item

r2d2b2g will install the app and start B2G Desktop so you can see the app the way it’ll appear to Firefox OS users:

B2G Desktop


Try It Out!

Note that r2d2b2g is an experiment, not a product! It is neither stable nor complete, and its features may change or be removed over time. Or we might end the project after learning what we can from it. But if you’re the adventurous sort, and you’d like to provide feedback on this investigation into a potential future product direction, then we’d love to hear from you!

Install r2d2b2g via these platform-specific XPIs: Mac, Linux (32-bit), or Windows (caveat: the Windows version of B2G Desktop currently crashes on startup due to bug 794662 795484), or fork it on GitHub, and let us know what you think!

About Myk Melez

Myk is a Principal Software Architect and in-house entrepreneur at Mozilla. A Mozillian since 1999, he's contributed to the Web App Developer Initiative, PluotSorbet, Open Web Apps, Firefox OS Simulator, Jetpack, Raindrop, Snowl, Personas, Firefox, Thunderbird, and Bugzilla. He's just a cook. He's all out of bubblegum.

More articles by Myk Melez…


  1. Stephanie Daugherty

    Awesome work. Let’s hope this evolves into the preferred way to test, it leaves other smartphone dev/test environments in the dust, and that’s a great thing,

    October 2nd, 2012 at 16:31

    1. Robert Nyman

      Thank you very much, glad to hear that!

      October 3rd, 2012 at 03:57

  2. Michael Fitzpatrick Ruth

    Should be put into the Web Developer menu in firefox for users who hide the old style menus

    October 2nd, 2012 at 16:47

    1. Robert Nyman

      I believe it’s not really in that state yet, though, so it wouldn’t be optimal to mix with implemented/shipped features. Evaluating other menu options could be an idea, though.

      October 3rd, 2012 at 03:58

    2. Myk Melez

      It’s a good point, although ultimately I expect this interface will not be menu-based. But if there’s any menu entry point in the Tools > Web Developer, then it should also be in Unified Menu > Web Developer on platforms where Firefox has a unified menu.

      October 3rd, 2012 at 10:35

  3. Ashish

    Did not work on my laptop. The simulation crashed as soon as I launched it. Tried restarting the browser. Are there any special hardware or software requirements for this ?

    October 2nd, 2012 at 23:11

    1. Olly Hodgson

      Alas the Windows version of B2G desktop is rather crashy at the moment.

      October 3rd, 2012 at 03:25

      1. Pahellebrand

        Windows is crashy! :D

        October 9th, 2012 at 22:13

    2. Robert Nyman

      Not really, that I know of. Please file a bug with as many details as possible.

      October 3rd, 2012 at 03:59

  4. Aleks Totic

    This is really nice. I wanted to see how far b2g has come. I was sad when my b2g build failed yesterday on Mountain Lion. I’ve just ran r2d2b2g, and now I am happy. Great job.

    October 2nd, 2012 at 23:18

  5. Jean Claveau

    + A button would be nice when you have no “tools” menu (menu bar hidden on Linux or Windows).
    + Commands Super or Fn+left or esc don’t work on Xubuntu.
    + It crashed soon (console included but the rest of Firefox stayed ok).
    + This is a f*****g awesome idea!!! Wouldn’t it be possible to take benefit from profiler/crash reporting/qa… to boost b2g developments/tests?

    Conclusion : b2g begins to have best features/tools than the others! Love it!

    October 3rd, 2012 at 02:07

    1. Robert Nyman

      Thanks for the feedback and kind words!
      We’ll see how to move forward from here.

      October 3rd, 2012 at 04:00

    2. Myk Melez

      I experimented with a toolbar button in an earlier version, and I could imagine reintroducing it.

      I’m not sure why those shortcuts didn’t work on Xubuntu. Did you try using the Home key on your keyboard to return to the home screen? Mac keyboards don’t have them, but other keyboards do, and the Home button is the equivalent to Fn + Left Arrow on a Mac keyboard.

      Sorry about the crash! But glad to hear you like the idea! B2G Desktop does come with the crash reporter, and the Report a Crash dialog should appear when B2G Desktop crashes. It sounds like it didn’t in your case, though, and I’m not sure why.

      October 3rd, 2012 at 10:41

  6. gvnmcknz

    r2d2b2g up and running on Xubuntu.

    Now where’s the Apps?

    I’m just an ordinary user.
    Bit of a distro-hopper, (guaranteed to get it going wrong like most folks will).
    Tried AndroidX86, got RaspberryPi etc..
    So ideal guinea -pig really!

    Or do I need to sign for a Beta?

    Anyway, good work, looking forward to further progress.


    October 3rd, 2012 at 03:47

    1. Robert Nyman

      Good to hear!
      You have a few default apps, but otherwise you can use the menu option Install Page as App to get the current visible web page added.

      October 3rd, 2012 at 04:02

  7. Richard Vidler

    Great idea! installed it on FF on Win7 but as stated it’s too ‘crashy’ to be useful (just about manage to swipe the slider when it crashes :()
    As soon as I’m back in the office I’ll try it on my CentOS laptop, I have a few sites that I’d love to test as Apps.
    Is r2d2b2g close to the current B2G in features etc?

    October 3rd, 2012 at 04:56

    1. Myk Melez

      Richard: good question! r2d2b2g bundles B2G Desktop, which simulates the experience of Firefox OS on a phone. It is fairly close to that experience in some respects: like the presentation of home screens and interaction via simulated finger swipes and Home button presses. Also, apps run in the same rendering engine as the one on the phone. But some APIs, especially those tied to hardware features of the phone (f.e. accelerometer), may not be present or may not work correctly. And there isn’t yet support for things like changing the orientation.

      I’m still learning about the similarities and differences myself! And also which missing features are most important to add. Your feedback is welcome!

      October 3rd, 2012 at 10:56

  8. Guy

    64-bit Linux please? :D

    October 3rd, 2012 at 22:08

    1. Robert Nyman

      We’ll see. :-)

      October 3rd, 2012 at 23:50

  9. Guy

    Cool, if you happen to do it, and happen to think about it, I wouldn’t mind an email letting me know. Will keep checking back though.

    Thanks :)

    October 4th, 2012 at 07:38

    1. Myk Melez

      Bug 776845 tracks building B2G Desktop for 64-bit Linux. As soon as that build is available, I’ll build a version of r2d2b2g with it. So cc:ing yourself to that bug is a great way to monitor progress on this issue!

      October 4th, 2012 at 09:17

  10. Martijn

    How can you be sure that you get the latest nightly from b2g/gaia?

    October 4th, 2012 at 10:09

    1. Myk Melez

      The addon bundles B2G/Gaia, so getting the addon doesn’t give you the latest nightly. But it does give you a recent version that is known to work with the functionality provided by the addon. And I plan to update the version of B2G/Gaia in the addon on a regular basis.

      October 4th, 2012 at 12:13

  11. Ignacio Agulló Sousa

    At Ubuntu 12.04 it installs successfully, but then fails to work. After installing it as a firefox extension for user nacho, you get three new items at the Tools menu – this is what happens when trying them:

    1 B2G Desktop: Opens both an unnamed window (with a wallpaper, date and time, and three unresponsive icons) and an “Error Console” window which reads “Failed to load native module at path ‘/home/nacho/.mozilla/firefox/t279uql5.default/extensions/r2d2b2g@mozilla.org/resources/r2d2b2g/data/linux/b2g/components/libmozgnome.so’: (80004005) /home/nacho/.mozilla/firefox/t279uql5.default/extensions/r2d2b2g@mozilla.org/resources/r2d2b2g/data/linux/b2g/components/libmozgnome.so: cannot open shared object file: No such file or directory”

    2 B2G Desktop Helper: Does nothing noticeable

    3 Install Page As App: Shows a system message reading “Installed r2d2b2g: an experi” and then closes both the unnamed windows and the “Error Console” window

    October 5th, 2012 at 04:44

  12. Ignacio Agulló Sousa

    Tried an easy fix to the problems reported on the previous comment – sought for the “libmozgnome.so” file, and found four inside /usr/lib/:
    -At firefox/components/
    -At seamonkey-2.4.1/components/
    -At thunderbird/components/
    -At xulrunner-
    Copied the one from firefox components at the user path .mozilla/firefox/t279uql5.default/extensions/r2d2b2g@mozilla.org/resources/r2d2b2g/data/linux/b2g/components/
    And then, I when try the B2G Desktop menu item, again I get the two windows, the unnamed one and the “Error Console” one, reading “Native module at path ‘/home/nacho/.mozilla/firefox/t279uql5.default/extensions/r2d2b2g@mozilla.org/resources/r2d2b2g/data/linux/b2g/components/libmozgnome.so’ is incompatible with this version of Firefox, has version 15, expected 18.”

    October 5th, 2012 at 04:50

    1. Myk Melez

      Ignacio: Sorry to hear about your problems getting r2d2b2g working! Are you using a 64-bit version of Ubuntu 12.04 by any chance? The 32-bit build of B2G Desktop that the Linux version of r2d2b2g includes is known to have problems working on 64-bit versions of Linux. There should be a workaround, but I haven’t quite worked out what it is yet!

      October 5th, 2012 at 15:04

  13. Ken Saunders

    I experienced crashes (Win7) as others and with all versions from labs/r2d2b2g.

    Has anyone taken the time to file a bug for the Windows crashes? I searched but couldn’t come up with any bugs at all.
    I’d love to help out, but there isn’t a component under Labs (and wouldn’t be sure of what to offer). Is that what it would go under?

    Update: 1
    I am able to run it with a new 15.0.1 profile.

    I saw the following and have no clue if it’s helpful.

    Timestamp: 10/5/2012 10:46:38 AM
    Error: this.webapps[msg.id] is undefined
    Source File: resource://gre/modules/Webapps.jsm
    Line: 395

    The error console always appears when launched in all instances.

    After some digging I found these.
    I believe that 3 are duplicates.


    Crash ID: bp-43c393f7-cf59-4c0f-bdae-538442121003
    Crash ID: bp-478f8181-83b1-48fc-8e9a-41dbd2121005
    Crash ID: bp-032e9328-503e-4cd2-9aa0-1c1872121003
    Crash ID: bp-7cfbdb6f-ed60-4463-a4d0-5ade52121003

    When I used to use the old (early) mobile emulator there were startup issues as well. Perhaps digging up what they were would help if what I’ve provided isn’t helpful.

    Martin Brinkmann (Senior Editor and Founder of Ghacks)
    “I can’t really say anything about the functionality due to the crashes”

    October 5th, 2012 at 09:27

    1. Myk Melez

      Ken: the bug on the Windows crashes is bug 795484!

      October 5th, 2012 at 09:36

  14. geraldo

    Works like a charm on Ubuntu 12.04 32bit. Thanks for the work!

    October 6th, 2012 at 15:06

    1. Robert Nyman

      Good to hear!

      October 9th, 2012 at 23:32

  15. Brandon Cheng

    Appreciate your work! It’s nice to see B2G/Firefox OS this easily deployed for testing. :)

    October 9th, 2012 at 22:15

    1. Robert Nyman

      Thank you, we’re happy to hear that!

      October 9th, 2012 at 23:33

  16. Gabriela

    Crashing in Windows 7! I have cc’d myself to the Window’s crashes bug to be able to follow it.

    October 10th, 2012 at 06:25

    1. Robert Nyman

      Thanks. Hopefully we can get that fixed.

      October 14th, 2012 at 05:14

  17. Kelvin S

    I get this terminal error on Ubuntu 12.10:

    info: r2d2b2g: Error while loading localization: There is no localization file for your language.
    info: r2d2b2g: linux/b2g/b2g-bin terminated with 0
    Running global cleanup code from study base classes.

    October 10th, 2012 at 12:26

    1. Robert Nyman

      Can you please file an issue about that?

      October 14th, 2012 at 05:15

  18. Jonathan W.

    After actually using it, I can say that, while it has some features resembling Android and some resembling iPhone, B2G does a good job of making the general user experience attractive and easy to use. I just hope a certain fruit based company doesn’t try to sue B2G to death.

    October 10th, 2012 at 18:26

    1. Robert Nyman

      Thanks, glad you like it!

      October 14th, 2012 at 05:14

  19. Rodolfo De Nadai

    Oww!! This is awesome! A little buggy on my linux mint with cinnamon (the back key [ESC] don’t work)… but that’s a great feature!
    As someone point out, this make FirefoxOS far ahead! :D

    October 12th, 2012 at 16:37

    1. Robert Nyman

      Thank you!

      October 14th, 2012 at 05:15

  20. Jean Claveau

    I was just testing the new startup profiling and saw that :

    Is there a bug, bound to r2d2b2g, somewhere I can post it?

    October 16th, 2012 at 02:41

    1. Myk Melez

      Hey Jean, I’m not sure what that link is representing, although it looks pretty cool! Can you explain further?

      October 18th, 2012 at 16:18

      1. Jean Claveau

        Benoit Girard from the the snappy project’s team implemented the SPS Profiler (https://developer.mozilla.org/en-US/docs/Performance/Profiling_with_the_Built-in_Profiler) a few month ago.

        One of its early feature is a restart of the browser to measure the cost of operations… at startup.

        So I tested it and saw that r2d2b2g costs 121ms on my machine (still at startup) and the stack I posted shows it.

        This is quite a big waste so I thought it is a good idea to warn!

        Btw, your really should use this profiler (if you don’t already), it’s a pearl.

        October 19th, 2012 at 04:31

  21. Myk Melez

    Jean: Ah, ok, now I understand. And that’s very useful information, thanks for bringing it to our attention!

    I filed issue 28 about it, and I also posted about it to the Jetpack discussion group. Feel free to participate in the discussion in either or both of those two places!

    October 19th, 2012 at 09:18

  22. OLLI_S


    when will B2G run on WIndows machines?
    Will the Add-on auto-update itself?



    October 23rd, 2012 at 12:33

  23. Andre

    Still not running on Windows (Windows 7 x64).
    I’m looking forward to it!

    October 31st, 2012 at 02:17

  24. Gabriela

    Oh, yes!!! Please fix it for Windows as soon as possible. I’ll be looking forward to it too!!!

    October 31st, 2012 at 16:18

  25. Myk Melez

    Folks, sorry about the wait for Windows support!

    We’ve identified a workaround along with a couple fixes for the startup crashes, and I plan to produce a stable Windows build next Wednesday, November 7. I’ll post here again on that day to let you know the build is available (or update you on the status if it has been delayed).

    November 2nd, 2012 at 13:31

    1. Gabriela

      Wow Myk, hurray and thanks!!!! :)
      I’ll be looking forward to your next post hoping it will be about a new build that doesn’t crash!!!

      November 2nd, 2012 at 13:48

  26. Christos Bacharakis

    Hello and thanks for that awesome post!
    The 64-bit Linux bug https://bugzilla.mozilla.org/show_bug.cgi?id=776845 is officially resolved?
    Can you provide us a build of r2d2b2g for 64bit Linux machine?
    Thank you!

    November 6th, 2012 at 04:17

  27. Andrea

    r2d2b2g 0.5 – 0.5.1

    Errore: ERROR addons.xpi: extractFiles: failed to create target directory for extraction file = C:Documents and SettingsAdministratorDati applicazioniMozillaFirefoxProfilesxxxxxx.defaultextensionsstagedr2d2b2g@mozilla.orgresourcesr2d2b2gdataprofilewebappsmarketplace-devcachemarketplace-dev.allizom.orgtelefonicamediaimgmkt: [Exception… “Component returned failure code: 0x80520011 (NS_ERROR_FILE_NAME_TOO_LONG) [nsIFile.create]” nsresult: “0x80520011 (NS_ERROR_FILE_NAME_TOO_LONG)” location: “JS frame :: resource:///modules/XPIProvider.jsm :: extractFiles :: line 1105” data: no]
    File sorgente: resource:///modules/XPIProvider.jsm
    Riga: 1105

    November 6th, 2012 at 04:21

    1. Myk Melez

      Andrea: it sounds like you are experiencing a limit in the maximum file path length on Windows. Files are limited to 260 characters by the Windows API (as described in this article), and r2d2b2g has a complex directory hierarchy that can run into that limit.

      I filed issue 78 in our issue tracker to track the issue. Thanks for reporting it!

      November 8th, 2012 at 10:18

  28. Myk Melez

    New builds are now available! The Windows build no longer crashes on startup, and the Linux build now supports 64-bit systems.

    The links to download the latest build remain the same:

    Mac: https://ftp.mozilla.org/pub/mozilla.org/labs/r2d2b2g/r2d2b2g-mac.xpi
    Windows: https://ftp.mozilla.org/pub/mozilla.org/labs/r2d2b2g/r2d2b2g-windows.xpi
    Linux: https://ftp.mozilla.org/pub/mozilla.org/labs/r2d2b2g/r2d2b2g-linux.xpi

    Note that the menu item that opens the simulator interface has now moved into the Web Developer menu and been renamed to Firefox OS Simulator.

    Give these builds a try, and let us know how they work for you!

    November 8th, 2012 at 09:56

  29. OLLI_S


    I am using Firefox 16.0.2 in WIndows 7 Professional x64.
    It works perfectly, thank you!

    Just one question: how can I go back from an app to the home screen?
    The emulator has no home button.



    November 8th, 2012 at 13:07

    1. Myk Melez

      OLLI: in the latest version, 0.6, there should be a Home button, with an icon in the shape of a house, at the bottom center of the simulator window. Does that not show up for you?

      November 8th, 2012 at 14:38

      1. OLLI_S


        I checked it, I have version 0.6.

        When I start the simulator, a new tab opens (Simulator Dashboard).
        Here I click on “Stopped” to start the simulator.
        A new window opens (lock screen) and I am unlocking it.

        I only see the window with:
        – notification bar at the top (showing the time)
        – home screens
        – at the bottom of the home screen some icons like “Firefox” or “Calls”.
        Below those icons the window ends.

        I can resize the window (change the height) and I get a black area at the bottom.
        But there is NO home button.

        If I start the simulator using the Java console, I get some messages that might interest you.
        Here I copy just warnings and errors.

        Timestamp: 10.11.2012 11:13:31
        Warning: Unknown property ‘-moz-align-self’. Declaration dropped.
        Source File: resource://gre-resources/ua.css
        Line: 44

        Timestamp: 10.11.2012 11:13:31
        Warning: Error in parsing value for ‘vertical-align’. Declaration dropped.
        Source File: app://system.gaiamobile.org/style/crash_reporter/crash_reporter.css
        Line: 2

        Timestamp: 10.11.2012 11:13:32
        Error: [Exception… “Component returned failure code: 0x80570015 (NS_ERROR_XPC_CI_RETURNED_FAILURE) [nsIJSCID.createInstance]” nsresult: “0x80570015 (NS_ERROR_XPC_CI_RETURNED_FAILURE)” location: “JS frame :: resource://gre/modules/ActivitiesService.jsm :: actdb_createId :: line 77” data: no]
        Source File: resource://gre/modules/ActivitiesService.jsm
        Line: 77

        Timestamp: 10.11.2012 11:13:32
        Error: TypeError: _conn is undefined
        Source File: app://costcontrol.gaiamobile.org/js/service/cost_control_service.js
        Line: 203

        There are also some messages like
        Content JS WARN at app://system.gaiamobile.org/shared/js/l10n.js:764 in getL10nData: [l10n] #statusbarTimeFormat is undefined.

        Are they also interesting for you?

        I did not find a way to copy the entire JS Cosole at one (copy all).
        Just tell me what you need.
        Do you also need a screen shot?



        November 10th, 2012 at 03:16

        1. Myk Melez

          OLLI: thanks for the detailed info!

          The console messages are probably not relevant, but a screenshot would be great! However, before you take a screenshot, try installing the latest version (0.7), which I just built yesterday, to see if it happens to solve your problem.

          Also, note that I have reported this as issue 102 in our issue tracker. Follow that issue to keep up-to-date on any progress we make resolving it! (Unfortunately, at this point I still can’t reproduce the problem, which is the first step to resolving it; but hopefully soon I’ll be able to do so!)

          November 15th, 2012 at 12:32

          1. OLLI


            in version 0.7 I see the home button!
            Thank you very much for your great work!



            November 15th, 2012 at 13:47

        2. Myk Melez

          One more thing! Even without the visible Home button, you can go back to the homescreen by using the Home key on your keyboard as a keyboard shortcut.

          November 15th, 2012 at 12:33

  30. Ken Saunders

    Thanks a lot for fixing this!

    When I click on “Open Location” after adding an url (in the Dashboard), shouldn’t the app/page be launched in r2d2b2g?
    It’s currently opening in the desktop browser whether r2d2b2g is running or not.

    Also, what functionality does r2d2b2g have?
    Do you have any documentation on that?

    One last thing. Where are the generated app manifest files stored?

    November 8th, 2012 at 16:38

    1. Myk Melez

      Sorry about the confusion! *Open Location* is actually intended to show you the app in a Firefox tab. To see it in the simulator, start the simulator and find it on the homescreen; or, as of the latest version, 0.7, you can press the Update button, which will update the app in the simulator and then automatically start (or restart) the simulator and go to the app.

      I actually find this confusing too, and I’ve mentioned it to Kevin, the product manager.

      November 15th, 2012 at 12:35

  31. Gabriela

    It works fine for me too, I do have the Home button. Many thanks for the hard work to fix it for Windows!!!!
    Firefox crashes though :(

    November 8th, 2012 at 16:40

    1. Myk Melez

      Hi Gabriela,

      Sorry to hear Firefox crashes for you! If you give me additional information, I might be able to diagnose the problem. When does it crash for you, and does it do so everytime or just some of the time?

      Note also that I released an updated version, 0.7, yesterday. And it includes some bug fixes for Windows. So you might give it a try and see if it works any better for you!

      Here is the latest version for Windows.

      November 15th, 2012 at 12:38

      1. Gabriela

        Hi Myk,

        I have installed the updated version and Firefox isn’t crashing any more, many thanks for your hard work!

        However, vertical and horizontal scrolling is impossible (scrolling bars don’t work as they should and mouse scrolling doesn’t work as it should either.
        Some sites display correctly, others don’t. Please take a look at the following screenshot:

        Should you like me to file a bug regarding any of this issues, just say so and I will!

        November 15th, 2012 at 13:18

        1. Myk Melez

          I’m glad to hear Firefox is no longer crashing for you!

          Scrolling (also known as panning) in Firefox OS is designed to work via finger tap-and-drag gestures, since that’s the kind of interface users have on mobile devices. The Simulator simulates this via mouse click-and-drag gestures (i.e. press down the mouse button, drag the mouse, then release the mouse button). When you use the mouse in that fashion, are you able to scroll?

          As for reporting sites not displaying correctly, it’s a good idea in theory, but I’m not sure how productive it will be in practice. The Simulator is designed to help app developers test their own apps, and we don’t necessarily ship the latest version of B2G/Gaia, so I’m not sure how B2G/Gaia developers will respond to bug reports about B2G/Gaia issues discovered using the Simulator. However, you could try reporting a bug in the Boot2Gecko product, Gaia::Browser component and see how developers respond.

          If you have additional issues with the Simulator itself, however, please do report them! You can even file an issue in our issue tracker, if you are so inclined.

          November 15th, 2012 at 14:21

          1. Gabriela

            Hi Myk,

            Many thanks for answering me so quickly!

            When I said scrolling didn’t work as it should, besides the scrollbar issues I meant the way you say: via mouse click-and-drag gestures (i.e. press down the mouse button, drag the mouse, then release the mouse button). I meant this way it doesn’t work. Dragging the mouse to the right for example, does not slide the site as it should and it slides around anywhere till I press down the mouse button again.

            I will try reporting the display issues as you suggest sometime later or during the weekend and I’ll see how the developers respond.

            November 15th, 2012 at 14:31

  32. qunow

    May I know what’s the min. firefox version required to run the plugin? My Firefox 9.0 said it is not compatible with it, and i can’t upgrade that firefox as that is locked..

    November 13th, 2012 at 19:09

  33. Myk Melez

    Hi qunow: unfortunately you need to have at least Firefox 16 (the current stable release) to install and use the simulator. Is it possible for you to install a second copy of Firefox at a different location? That might enable you to work around the problem that your existing installation of Firefox is locked.

    November 15th, 2012 at 12:40

  34. Ken Saunders


    @qunow (this is for Windows)
    Download the latest version of Firefox.
    When you start the installation, in Setup Type select Custom > Choose Install Location > Browse > create a new folder in whatever location that you’d like (name it whatever) > OK.
    After it’s installed, don’t run it yet.
    Go to the folder that you installed Firefox into.
    Find the firefox.exe.
    Right click on it and drag it to your desktop > Create shortcuts here.
    Right click on that select Properties > Shortcut (tab) and in the Target line, paste the following at the very end > Apply > Ok.
    -no-remote -p
    So, it will look something like this.
    “C:Program FilesMozilla Firefox Releasefirefox.exe” -no-remote -p

    Now when you double click on that, the Profile Manager will open.
    Uncheck > Don’t ask at startup.
    Select Create Profile, when done, Start Firefox and you’ll be good to go.

    There are number of ways to do all of this but once you, and anyone else learns it, you’ll be able to run several different versions of Firefox so you can start exploring and help testing Beta, Aurora, and Nightly versions of Firefox, you can run them along side each other (multiple instances), and you won’t mess up your primary, or default Firefox profile. You just create a new profile for each.

    After all of this, you’ll be on your way to becoming a Mozilla tester and if you’d like, a contributor.
    That was the purpose of hijacking this post. Well, and I wanted to help you. :)

    I’ve never done this on Mac, but I have on Linux (a bit different than above)
    Any questions or problems, feel free to contact me.

    KenSaunders at AccessFirefox .org

    Also see
    “Installing and running multiple versions of Firefox”

    November 16th, 2012 at 08:30

  35. yanglifu90

    Why it is named r2d2b2g? What does ‘r2d’ mean?

    March 15th, 2013 at 03:13

    1. Robert Nyman [Editor]

      It stands for “Ready to Deliver to Boot to Gecko”. Boot to Gecko has been the code name for Firefox OS. It’s also a nod to the R2D2 robot in Star Wars.
      It’s now named Firefox OS Simulator.

      March 15th, 2013 at 03:36

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