Experimental Firefox OS software for Xperia™ E available for developers [ROM]

Earlier this week, Sony and Telefónica announced in a joint press release that we are evaluating the Firefox operating system for mobile phones. To show you our current progress, we now also provide an experimental version of the Firefox OS software for Xperia™ E, so that advanced developers can try it out and so that we can get valuable community feedback. In this article, we give you the background of Firefox OS, instructions how to flash Firefox OS on Xperia™ E, as well as an introduction to how to start developing applications for Firefox OS.

Firefox OS is a new mobile operating system built entirely upon open web standards, and Sony is interested in exploring this technology with Telefónica to help bring the power of the web to mobile. This sentiment is further expressed by Bob Ishida, Deputy Chief Executive Officer and Head of Products Business Group at Sony Mobile Communications, who says:

“At Sony Mobile, we continue to evaluate innovative technologies that can help deliver the premium user experiences that Sony’s consumers expect. Our engineers are now working with Firefox OS Mobile and HTML5, evolving technologies which show great potential.”

Now we’re ready to share our initial experiments on Firefox OS with the tech community, to get valuable feedback. More importantly, we want to reach out to the application community and support the early adopters who can start to develop applications for Firefox OS. Therefore, Sony experts Andreas Sandblad and Per Åstrand have put to together an experimental Firefox OS ROM for you to flash on Xperia™ E.

This software is not intended for daily use, and several important limitations apply. You can read more about this in the section “How to flash Firefox OS on Xperia™ E” below, but first Anders Isberg, Web Researcher from Sony, will introduce you to the Firefox OS.

An introduction to Firefox OS – the newest mobile platform
Firefox OS is based on the idea of taking the web application model a step further and enabling support for all types of applications. This includes applications that today are done with native programming languages, such as the camera application or the traditional dialler application. To facilitate these requirements, Firefox OS provides a richer set of device APIs compared to traditional web browsers.  In addition to traditional web browsers, Firefox OS also have a privileged access model for applications. This ensures that applications cannot access sensitive APIs without proper authorization.

One of the cornerstones of the web application model is the openness, which is one of the reasons for the popularity of web. Therefore, it is essential that this technology becomes standardised to avoid creation of new proprietary technology. W3C has established a new working group, Web System Application working group, which has support by a broad range of players in the industries. Sony also supports this initiative, and we are committed to contribute to the work of defining a new standard for web system applications in W3C.

The architecture of Firefox OS
Now let’s take a brief look on the Firefox OS software architecture. In simplest terms, Firefox OS consists of three key components:

Illustration of the Firefox OS architecture.

  • Gonk, which is the middleware that consists of a Linux kernel together with several software libraries and a hardware abstraction layer. Gonk runs on top of the mobile chipset that includes hardware and device drivers.
  • Gecko, which is the application runtime that implements the HTML5, CSS and JavaScript execution environment.
  • Gaia, which is the user interface in Firefox OS and provides the home screen and application launcher user experience.

Since Firefox OS’s primary application model is based on web technologies, there is no real concept of native applications. All user experience are developed using HTML, CSS and JavaScript technologies.

How to flash Firefox OS on Xperia™ E
Now that you have a basic understanding of Firefox OS, and if you’re ready to start tinkering with it on an Xperia™ device (for now, Xperia™ E), the next step is to flash Firefox OS on it. Before you flash this experimental ROM, please consider the following carefully:

  • Before you unlock the boot loader, make sure that you have read and understood that unlocking the boot loader may void the warranty of your device.
  • You must be using an unlocked Xperia™ E. It will not work on a locked Xperia™ E.
  • You should be an advanced developer with extensive knowledge in how to flash and switch between different ROMs. If you are a consumer without these developer skills, then we strongly recommend you not do try this as you may damage your phone.
  • Some of the features are not switched on or implemented:
    • No radio connectivity available, due to that this software has not passed certification and type approval. This means that you cannot make any phone calls or use Wi-Fi or Bluetooth.
    • The functionality of the SD card might be unstable.
    • The touch sensitivity is not fully calibrated.

This software can be flashed on an Xperia™ E that has similar hardware specifications as the initial scope of the first version of Firefox OS and is therefore a natural candidate.

Flash Firefox OS on your Xperia™ E by performing the following steps:

  1. Unlock the boot loader using our unlock boot loader service. Note that the possibility to unlock a device can sometimes be restricted due to operator restrictions. Also note that once you’ve unlocked your phone, you will not get any official software updates from Sony.
  2. Download and install the flash tool for Xperia.
  3. Start the flash tool and connect your phone as described in the flash tool instructions. When you connect your unlocked Xperia™ E, the Firefox OS software will be available to flash. There is also a standard Sony software version that you can flash, if you want to go back to Android™ from the Firefox OS software.

If everything went well, your device is now ready to boot with Firefox OS. Turn on the power and after the initial boot sequence, you can start to explore Firefox OS.

How to build apps for Firefox OS
One of the most exciting aspects of web-based devices is that there is already a well established ecosystem for application developers. If you have already developed web applications, you can continue to use your favourite tools. However, before starting to implement your first application, there are some resources that are useful to consult. The Mozilla Developer Network  has an extensive set of documentation on how to get started with Firefox OS development. There you will find information about how to write an application, the privileged access model, emulators, debugging instructions and considerations to get good performance.

If you are used to develop web apps, you will immediately recognise the way of developing applications. However, one key component that is added is the concept of manifest files. The manifest file contains extra metadata about the web application, to make it installable. For example, the following information could be declared in the manifest:

  • path to the application
  • privileged API access
  • localization data
  • links to different icon resources

Once the app is developed and the manifest is created, the application can be installed on your device. If you would like to share your first applications, it is possible to self-host the applications on your own server by adding some lines of code into your web page. Here is an example of how to self host an application.

Let us know what you think of Firefox OS on Xperia™ E
If you plan on using the Firefox OS software and get started on your mobile web development, we’re very eager to get the community feedback of your experiences with Firefox OS on Xperia™ E. Let us know what you think in the comments below. And if you publish your apps, feel free to share the link in the comments field!

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  1. By F Pauwelyn


    I bought the xperia E with the promise Firefox OS would run on it. But more than a year later still no update, while Firefox OS phone can be bought allready ? Why ever buy a sony phone again. They didn’t upgrade the android version either.

  2. By Dylan Irzi



  3. By Jozef Cmar


    Is there any progres about Firefox OS? I know that core function will not work, but is there any update from February 2013? Thanks

  4. By Jere Samuli Perttula


    Hi, Anna Aleryd,
    is there going to be any updates on the Firefox OS for Xperia E? I would really like to start using it, but as there is no connectivity I cannot use it.


    • By Naman Sood


      I’m hardly an expert in this matter (just the owner of an Xperia E), but I doubt this’ll ever happen. This build seems more of a rushed proof-of-concept, they didn’t even wait for approval for GSM, WiFi and Bluetooth.

      If Sony releases another build after this, I provoked them into acting, you’re welcome. ;)

  5. By Serge Zaitsev


    Hi, Anna!

    It’s been 8 months since this announcement. Are there any news about Firefox OS for Xperia phones? Since Firefox OS is a “web os” – that would be really nice to have some kind of web access on the phone (e.g. WiFi, or mobile internet), which means having a working radio. However, seems like Sony didn’t make any further steps in this direction. Anna, can we expect for working radio on Xperia E/Firefox OS any time soon?


  6. By Udit Jhalani


    I wanna know that how to root my device !
    Please help me out ! :-!
    Thanks in advance.!

  7. By Jere Samuli Perttula


    Is there going to be a fully working build of Firefox os for Xperia E and when will it be released? I’d really like to make the switch already but as there is no cellular, wifi or bluetooth connectivity this can’t be used as a phone.

  8. By alejandro garcia


    upgrade to firefox 1.1.0 there will at some future

    • By Rafal Matak



      Do you know how to upgrade to firefox 1.1.0?



    • By Anna Aleryd



      You don’t have to register or log in to use the flash tool. Just make sure you have the customization.ini file in the right folder, as described in step 4 and 5 on the installation page.

      Anna from Developer World

  9. By Sascha Dech


    Hi Anna,

    Would it be possible to give a hint if you are planning to make WiFI or Cellular available for this ROM?
    I would love to use the device for App Development and specially for testing my apps.

    But away from the no Data Connection Problem, i really like the openness of Sony and the fast porting of this system. Great Job. Thanks a lot and it is really great to see it in an early stage like this.


    • By 王硚


      could u make it for xperia U?

      I want firefox os.

  10. By Ludomił Sawicki


    Are you willing to make another software for xperia go? Or maybe it’s useless? This rome would also fit?

    • By Anna Aleryd



      We are currently not planning to provide Firefox OS software for Xperia™ go. And as you can understand, this ROM only works for Xperia™ E, as all devices have their own specific configuration.

      Anna from Developer World

  11. By Fawad Hassan


    Is Sony going to update it regularly like Geeksphone is doing?

  12. By Benjamin Aylott


    Any word on an update which will enable the radio devices?

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