Windows 10 is coming this summer. Source: Microsoft

Forget the rumors about Apple (AAPL 0.89%) preparing to expand its smartphone recycling and trade-in program to Android and BlackBerry devices. Microsoft (MSFT 0.05%) appears to have developed a ROM with which Android users can flash their hardware to replace the pre-installed Google (GOOG 0.10%) (GOOGL 0.02%) operating system with Windows.

Microsoft is being assisted in this effort by Xiaomi, which is enabling Mi4 owners to flash the phones with the ROM to test out Windows 10. ROMs are much more common in China, where Google's presence is minimized due to censorship laws to which the company objects. As a result, Baidu (BIDU 0.80%) and other Web companies have created their own ROMs for users to install on Android phones.

If extended beyond the testing phase, the ROM could provide an easy way for Microsoft to get Windows 10 into consumers' hands without forcing them to commit to the OS.

Improving on 3%
Microsoft has largely failed to make a dent in most smartphone markets. Globally, Windows' market share is about 3%. The problem has been an inability to court developers, who aren't supporting the platform due to the low usage.

If users could simply download Windows like an app on Android, it could improve adoption. Of course, Google won't make that easy, likely blocking such an app from its Google Play store, but there are relatively simple workarounds. The point is, if users knows they can try Windows 10 without committing to either the hardware or software, they are much more likely to test it out.

It's easier said than done, though. Baidu created an operating system in 2011 to replace stock Google apps on Android with its own. The company slowly added new features to the OS to differentiate it from the version of Android most Chinese OEMs pre-installed, but adoption never increased despite Baidu's position in China's Internet search market. Earlier this month, Baidu announced that it would no longer update its operating system.

Likewise, Facebook faced similar difficulties with its Android skin, Facebook Home, in the United States. Adoption was poor -- again, despite the company's strong presence on the Internet -- and Facebook quickly shuttered the project.

There's no guarantee that opening the ROM to more handsets will increase adoption of Windows 10. But with most of the development work done already, it's certainly worth a shot.

Giving Windows away
Microsoft doesn't seem to have any issues providing Windows 10 for free. The company is offering all Windows 7 and Windows 8 users a free upgrade during the first year of availability. That's across all devices -- desktops, tablets, and smartphones.

This is part of Microsoft's shift away from Windows licensing fees, although businesses and manufacturers will still pay for a Windows license. Still, Microsoft has made it clear that if an individual consumer wants to try Windows 10, it wants to make it as easy and inexpensive as possible. It wouldn't be a leap for Microsoft to extend the same efforts to the significantly larger Android user base.

Microsoft is hedging its shortcomings with Windows adoption by extending its apps and services to Android and iOS. Its goal is to increase adoption of services such as Office 365, OneDrive, and Bing; while controlling the operating system would be ideal, it's not necessary for Microsoft to funnel users to its services.

Attacking the market from every angle
In Microsoft's quest to increase its share of the smartphone market, it needs to attack from every angle. The company must court developers and users at the same time.

For developers, Microsoft is leveraging its strong position in the PC market by unifying the operating system across all devices. That way, an app developed for desktop will also work on tablets and smartphones -- although the latter might need some UI tweaks. Combined with the free upgrade for Windows 7 and Windows 8 users, it could be a powerful tool to attract more developers to Microsoft's mobile platform.

Microsoft has also failed to attract mobile users, but giving them a risk-free chance to test the platform (perhaps right before their next smartphone purchase) could go a long way to improve adoption. Increased adoption opens the door for other revenue streams through its existing services, as well as increased app downloads, which generate billions of dollars in net revenue for Google and Apple.