Google's Android Open Source Project (AOSP) rolled out in 2007 with the goal of creating a unified framework for mobile operating systems and, in turn, expediting the development of mobile products. The core of the code was open to everyone, but to help guarantee quality products — and promote its own services in the face of Apple's iOS — Google also organized the Open Handset Alliance (OHA). Companies who pledged allegiance to this group effectively committed to certain standards of quality for any resultant Android hardware and software. Membership in the OHA, however, is not a requirement for AOSP and so numerous forked (read: compatible and non-compatible) versions, like Amazon's Fire OS, have been developed over the years. We've pinpointed just a few of these to highlight the vibrant — and often political — undercurrent of Android's alternate identities.
Amazon has always been in the business of selling things — be it books, groceries, clothes or electronic wares — giving it plenty of reasons to keep you within its own distinct ecosystem. And with an open-source framework like Android up for grabs, there was little need for the e-tailer to start from scratch with its own mobile products. So when the company unveiled its colorful Kindle Fire tablet in 2011, it did so with a modified version of the Android kernel. Amazon's custom software would later be called Fire OS.
It chose to deviate from the prescribed plan OHA that members had agreed upon and became a non-compatible “forked” version of the Android OS. That meant Google's app store (or software services suite) were absent from devices. (Functionality would have been compromised anyway, given its customization.) Instead, Amazon created its own app store with approved applications and offered users ways to buy and download digital products such as movies and music under the Prime umbrella. That "consumer" focus was amplified further with the 2014 release of the Fire Phone.
MI and UI
Xiaomi, rated the third-largest smartphone maker in the world by IDC last fall, has its own forked version of Android called MIUI that's reminiscent of Apple's iOS. The Xiaomi M1 (or Xiaomi Phone) was launched in 2011 and while the Chinese domestic versions didn't have Google's suite on board, some exported handsets did.
It's still a highly customized version of the OS, but it's been certified and is compatible with Mountain View's services (although there was some confusion for a time).
Alibaba, a massive online retailer (if you didn't know) had planned on loading its Aliyun OS on Acer's CloudMobile A800 handset in China back in 2012. That OS was a distinctly forked version and wasn't certified for Google's services. Google, however, laid on a good deal of pressure to end that deal. The problem being that Acer had signed on with the OHA and in doing so, had already agreed not to deal in incompatible devices.
Rooting for the underdog
After Android rolled out in 2008, a method for gaining root access to the system (aka rooting) was discovered. It allowed hackers to modify the existing system and reap the benefits of tweaks to an authentic build. Steve Kondik and his CyanogenMod OS emerged as its own offshoot of Android from this method. The more the merrier right? It's open-source, after all, and that's the name of the game.
Interestingly, in late 2013, Chinese smartphone maker Oppo released a special edition of its N1 smartphone running the CyanogenMod OS. The kicker was that the phone and its software passed Android's certification system, making it a first for this rebel OS and leading to a few interesting partnerships down the road.
Where Amazon's forked system was generally for corralling its sales and services into one isolated package, Geekphone's reasoning was all about security. The makers of Revolution — a multi-OS handset with an approved version of Android and Firefox OS — along with Silent Circle software offered this handset with PrivatOS.
Unsurprisingly, it's a non-compatible Android fork without certification, so you won't see any Google apps or services here. Considering that the Play Store can often be the medium for delivering malware, it's not necessarily a bad thing for a smartphone that prides itself on security. There is, however, something to be said for passing Android's official Compatibility Test Suite (CTS) and complying with its Compatibility Definition Document (CDD) for promoting a stable and efficient system.
Two partners = OnePlus One
Remember that CyanogenMod version of Oppo's N1? Steve "Cyanogen" Kondik and then-Oppo VP Pete Lau must have really hit it off when partnering to develop that handset. In November 2013, Lau resigned and soon after began to talk about his new company OnePlus, which would collaborate closely with Cyanogen for its "perfect Android flagship device," the OnePlus One.
Although notoriously difficult to obtain, the OnePlus was an underground hit at just $300. Instead of CyanogenMod, the One had Cyanogen OS (outside of China, at least), which wasn't open-source, but was certified to run Google's apps and services. The successful partnership that made this phone, however, was soon undone. In 2014, Cyanogen made an exclusive deal with OnePlus rival Micromax in India, leading to a breakup.
Cyanogen went on to promote its OS with various partners, most notably Microsoft. OnePlus shifted gears and developed Oxygen OS, which, after a few delays, managed to get Android certification itself.