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Firefox 4 Beta 2 for Android and Maemo Release Notes

Take your Firefox anywhere. Firefox 4 Beta for Android and Maemo is built on the same technology platform as Firefox 4 for desktop computers, just optimized for browsing on a mobile device. Check out the new and improved features, known issues and frequently asked questions. As always, you’re encouraged to provide suggestions to improve Firefox for mobile or file a bug in Bugzilla. If you need help, visit the Firefox Mobile Support Forum.

What's New in this Firefox 4 Beta

  • Reduced install size by 60% on Android
  • JavaScript performance is improved. Now 25% faster than stock browser on SunSpider.
  • Page loads are now around 40% faster than in beta 1
  • Battery usage has been reduced
  • Fixed problems that would cause you to get a black screen when launching the app
  • Reduced memory footprint
  • Improved text spacing
  • Now localized in 10 languages
  • New theme
  • You can now undo closing a tab
  • The native Android sharing system is now used when you share a link
  • Desktop notifications are now supported
  • Finger friendly video controls
  • Content crashes will no longer take down the whole browser
  • Users will now be prompted to submit crash reports when the browser crashes
  • Beta tester tools for Android
  • Faster and more accurate multitouch zoom
  • Geolocation now works on Android

As well as these features from previous Firefox 4 Betas:

  • Sync - Shipping with the Firefox Sync feature built-in, Firefox 4 Beta synchronizes your Firefox history, bookmarks, open tabs, passwords and form data between your desktop and mobile. New users can now sync with their email as their username, along with their password and Sync Key.
  • Add-ons - Firefox 4 Beta offers add-ons; pieces of software that let you change or add features, functionality and the look of your Firefox to fit your browsing lifestyle.
  • Pinch-to-zoom (Android), double-tap, or use the volume rocker (Nokia N900) to zoom in and out
  • Tabbed browsing in thumbnail view lets you easily see and open the site you want
  • Location-Aware Browsing gives you content and info relevant to your location
  • Save to PDF in the Site Menu lets you archive important docs like tickets and directions to view offline
  • Find in Page in the Site Menu lets you quickly find text on the webpage
  • Share Page in the Site Menu lets you send content to email, Facebook, Twitter and Google Reader
  • Forget Password in the Site Menu tells a website you no longer trust to forget your private data
  • Add Search Engine in the Site Menu lets you quickly add a new search engine to your Awesome Screen
  • Context Menu lets you Open in New Tab and Share by long tapping and holding a link
  • Smart Tapping lets you tap on links, widgets and other Web content with accuracy
  • Password Manager lets you choose to remember site password to avoid typing

For Developers

Firefox is an easy and open development platform to build fast, powerful and beautiful mobile web apps and add-ons. Use the latest web technologies like HTML5, CSS and JavaScript to innovate faster, more easily and extend your reach. You can build great sites and apps by tapping into the device capabilities of the phone, as well as create game changing add-ons. Visit the Mobile Developer Network to learn more about how you can build and showcase your innovations on millions of devices.

Build add-ons for mobile

Although Firefox for the desktop and mobile are built on the same technology platform, there are differences that will require developers to make changes to their add-ons in order to become compatible with Firefox 4 Beta for Android and Maemo. Visit the Electrolysis and Add-ons wiki page and the Add-ons Training Week documentation to learn more.

What’s under the hood
  • The same browser engine as Firefox 4.0 beta for desktop
  • Fast JavaScript engine, using Mozilla’s “JaegerMonkey” just-in-time compiler
  • Leading Web compatibility
  • Engine optimized for ARM processors
  • Location-Aware Browsing
HTML5 Technologies:
  • Web workers
  • Offline storage
  • <canvas>
  • <svg>
Native JSON
  • <audio>
  • <video>

Known Issues

  • Firefox 4 Beta 2 now requires at least 17 MB of internal storage. If you are upgrading from Beta 1, you will need to uninstall before you install Beta 2 in order to see the size savings. You can do this by going to your Settings>Applications>Manage Applications> scroll downloaded Apps for Firefox and tap Uninstall.
  • Users who have a large desktop profile using Firefox Sync may see some performance issues. We are working to improve this in future releases.
  • Major changes to Firefox for mobile have been made which have resulted in multiple add-ons to break. Developers, please see the Electrolysis and Add-ons wiki and the Add-ons Training Week documentation to help you make your add-on compatible with Firefox.
  • Adobe Flash and other plugins are not supported yet.

User Interface:

  • Text does not wrap to fit the screen after zooming in, as it does in the Android browser (bug 578179). The Easy Reading add-on has some proof-of-concept code to do this.

Known Bugs:

  • 601222 - Firefox's JIT compiler is disabled on Samsung Galaxy S phones because of stability problems. JavaScript performance in Firefox 4 Beta will be slower on Galaxy S phones than on other devices.
  • 599811 - fn/alt/shift keys on Android keyboards need to stay pressed to register the next key entry
  • 535793 - Fennec will load an error page in place of the desired page while connecting to a network and loading a page at the same time
  • 609366 - If a user changes their network during the middle of a update, the browser packaging may break to the point a re-installation is required.

System Requirements

Firefox 4 Beta is available for download on the Android platform and on the Nokia N900.

Before installing Firefox 4 Beta on your Android phone, visit the Platforms and Device Requirements page to make sure your phone meets the Android system requirements.

See a full list of supported and unsupported devices by visiting our System Requirements wiki.


Download Firefox 4 Beta by visiting on your Android phone, or Nokia N900. Visit the Platforms and Device Requirements page to make sure your phone meets the Android system requirements.

Developers: You can download a version of Firefox for mobile to your desktop in order to test, provide feedback, and build add-ons. Desktop builds are for development purposes only and don't have full functionality:

Frequently Asked Questions

Is Firefox 4 Beta available for my phone?
Firefox 4 Beta is available for Android (2.0 and above) phones, and for the Nokia N900. See the Android System Requirements to see if Firefox 4 Beta is compatible with you Android device. You can download the Firefox 4 Beta here or, you can download Firefox 1.1 for the Nokia N900 here. If Firefox for mobile is not available for your device or platform, we're continuing to investigate ways to bring parts of the Firefox experience to you. Learn more about our mobile projects.
Is it called Fennec or Firefox?
Fennec is the codename of Mozilla’s mobile project, however, the official product name is Firefox. For pre-beta releases of Firefox, we call it by the project's name, Fennec.
How will Firefox keep me safe while I browse on my mobile?
Mozilla’s open source process leverages the experience of thousands of security experts around the globe, and Firefox includes features like instant Web site ID that checks on suspicious sites to ensure they’re what they claim to be. Customizable security settings to manage passwords, cookies, loading images and installing add-ons give you complete control over your browsing experience. Learn more.
How do I use the Firefox user interface to browse the Web?
To save space on your phone’s display, Firefox browser controls are stowed away to the sides of the screen. Swipe right to access your tabs on the left side of the screen. Swipe left to view one-touch bookmarking, back and forward, and access your browser tools. To let you see more of the Web site, your browser controls and Awesome Bar get stowed away out of view. when you scroll down a Web page, but they instantly reappear if you pan to either side. Tap on the on Web site ID to the left of the Awesome Bar to open the Site Menu to further manage your relationship with the Web page you are on.
What is the Awesome Screen?
The Awesome Screen pops up just by tapping on the location bar. It instantly brings up a smart list of your favourite history items and bookmarks and lets you easily select a search engine for your desired search. You can also customize your search engine list for maximum efficiency.
How do I zoom in and out?
For Android phones, pinch-to-zoom in and out or double tap. For the Nokia N900, you can use the volume button on the top of your phone, or double tap the screen with your finger to zoom in and out. Also, on the Nokia N900, Ctrl-up and Ctrl-down arrows will zoom in and out.
How do I bookmark a Web page?
Go to the site you wish to bookmark. Touch the bookmark “star” button on the right side of your display.
How do I open a new tab?
Touch the new tab "plus" button on the left side of your display screen to open a new tab. Tabs appear as thumbnails so you can easily see which page you’d like to select.
What are Firefox Add-ons and how can I get them on my mobile device?
Add-ons are small pieces of software that let you add or change the look or functionality of Firefox. Install add-ons directly to your Firefox by swiping to the left and tapping on the browser tools "gear" button on the bottom right-hand side of your screen, then choosing the add-ons “puzzle piece” button to discover and install the add-ons that are most useful to you.
How can I share my Firefox bookmarks, history, tabs, and passwords between my desktop and my mobile?
Firefox Sync is a built-in feature of Firefox 4 Beta that lets you synchronize your desktop and mobile data. To use this feature, you must first install Firefox 4 Beta for the desktop. Then go to Tools, Setup Sync and follow the prompts to create a Sync Account. (If you’re running Firefox 3.5 or 3.6 for the desktop, you must install the Firefox Sync add-on, restart Firefox and follow the prompts to createFirefox Sync account.

Then go to Firefox on your mobile phone, tap on the browser tools, and enter your Sync login info in fields provided in the Preferences pane. To learn more about setting up Firefox Sync on your mobile, watch this video.

Do I need to setup Firefox Sync to use Firefox 4 Beta on my phone?
No. Although we think Firefox Sync is highly useful, it is feature that you can choose to use or not. The Awesome Screen will start to get to know you and take you to your favorite parts of the Web with minimal typing, even without Firefox Sync.
What are the trade-offs to using Firefox Sync in Firefox 4 Beta?
Although we think Firefox Sync is highly useful, it is still in its experimental phase. Those who use Firefox Sync and who have large desktop profiles, may detect performance issues on their mobile. We are working to resolve this in future releases.
What is Location-Aware Browsing? Is Firefox tracking where I am?
Location-Aware Browsing saves you time by allowing websites to ask you where you are. If you choose to share your location with a website, it can use that information to find nearby points of interest and return additional, useful data like maps of your area. It’s all optional – Firefox doesn’t share your location without your permission. Learn more about Location-Aware Browsing.

Developer Questions

Will a Firefox add-on I built for the PC work on mobile? If not, do I need to change it?
Although Firefox for the desktop and mobile are built on the same technology platform, there are differences that will require developers to make changes to their add-ons in order to be compatible with Firefox for mobile. Visit the Mobile Developer Network and Electrolysis and Add-ons wiki to learn more.
What browser engine does Firefox use?
The desktop and mobile versions of Firefox both use the Gecko rendering engine. The mobile version of Firefox uses Gecko version 4.0b8pre, which is the best performing browser engine Mozilla has ever released and includes exciting features such as radically improved JavaScript performance, geolocation support, worker threads, and much more.
What JavaScript engine does Firefox use?
Firefox includes the new “JaegerMonkey” JavaScript engine, an advanced JIT (“just in time”) compiler using tracing technology. The JaegerMonkey engine makes Web applications faster by compiling code as you execute it, allowing many types of CPU-intensive applications to run at near-native speed.
How do I develop a Location-Aware website for Firefox?
Firefox has implemented the first public draft of the Geolocation specification from the W3C. An overview on how to develop Location-Aware websites here.
Does Firefox on my mobile support HTML 5?
HTML 5 is the next major revision of HTML. The HTML 5 specification is ongoing, but there are several HTML 5 and related features that will enable Web developers to create more innovative websites and applications. Firefox includes important features like Location-Aware browsing, the <canvas> and <svg> tags, Web workers and offline storage.
Does Firefox on my phone support plugins?
There is no plugin support in Firefox 4 Beta for Android and Nokia N900. On most Web pages that use the Adobe Flash plugin, the performance of the plugin didn't meet our standards, and the interactivity and performance of the entire Web page was negatively impacted. This was especially felt on pages with multiple instances of the plugin. Advanced users can enable plugins for experimentation and testing purposes only.
How can I get involved?
Help spread the word, test and improve Firefox 4 Beta and Go Mobile. If you’d like to learn more about ways you can get involved in other mobile-related initiatives, check out our Get Involved page. As always, your input is welcome.

View the Firefox 4 beta FAQ.