The effort to turn CyanogenMod into the next big mobile operating system just got a big new vote of confidence. The company announced today that it has raised an additional $23 million, led by Andreessen Horowitz, to add staff and improve its distribution around the world. The series B round, which comes on top of $7 million that the company closed in April, shows that investors are betting the world is clamoring for a different take on Android. “Mobile has really just begun,” says Kirt McMaster, Cyanogen’s CEO. “Apple, Google, and Samsung have not won. Although it seems like they’ve won, it’s still early days.”

There’s some data to back up the big talk: CyanogenMod now has 11 million active users, up from 8 million in September, and that counts only those who have elected to share data with the company. The true number of CyanogenMod users is already in the tens of millions, says Andreessen partner Peter Levine — and that’s despite some significant distribution challenges. One guide for installing CyanogenMod on your Android smartphone lists 23 steps; the company released a one-click installer this fall, but was forced to remove the companion app from the Google Play store after Google said it violated the store’s terms of service. Licensing issues also mean that a freshly installed Cyanogen ROM doesn’t come with Google apps or the Play Store — users typically have to search online forums for links to those apps and install them via PC. These are all significant hurdles to mainstream adoption.

Cyanogen now has 11 million monthly active users

So where’s all the growth coming from? Initially, Cyanogen’s custom ROM found favor with hobbyists in the United States and abroad who preferred it to the often bloated versions of Android promulgated by carriers. The ROM strips Android down to a near-stock version while customizing it with a new camera app, secure messaging, and access to thousands of themes. It has also proven a godsend to owners of older devices who are abandoned by their carriers.

But Cyanogen has also found favor with Chinese smartphone manufacturers. Xiaomi’s MiUI operating system is based on Cyanogen, for example, and Oppo’s N1 is shipping with CyanogenMod preinstalled. Emerging markets have begun to embrace it as well, particularly in India, where merchants are flashing used smartphones with the latest version of Cyanogen and reselling the devices. And it has begun to announce its first device partnerships, where Cyanogen is preinstalled on the phone.

The task now is to make Cyanogen more appealing to the mainstream. “We have to figure out a way to cross the chasm and get into the mass market,” McMaster says. “For that to happen, we have to do some things that are different.” Late next year, Cyanogen plans to unveil a new consumer brand. Among other things, it will be easier to say than “cyanogen.” The company is also working on what McMaster calls “signature experiences” — features no other operating system can offer. (The company won’t say what it’s working on, but the offerings will include “some things that scream out, like, ‘Fuck yeah,’ that’s really awesome,’” McMaster says.)

An installer that personalizes your phone

And while some see the Cyanogen installer as a hurdle to adoption, McMaster sees it as a potential benefit. The installer can evolve into software that personalizes your phone the moment it updates your firmware, so that when it restarts your device will be populated with custom wallpaper and apps you are likely to enjoy. But McMaster is likely understating the challenge: replacing a phone’s firmware can be difficult and risky. The reason Google wanted the Cyanogen installer app out of the Play Store is that installing it can void the warranty of many smartphones — something most mainstream users would rather not risk.

Now McMaster will begin rapidly expanding his team of 20, which is split between Seattle and Palo Alto. He plans to hire between 40 and 50 people over the next nine months — “enough to start doing some real damage,” he says." He says he is also confident that the one-click installer will return to the Google Play store; he has been in contact with Google to begin discussions.

And if investors are worried about the company’s relationships with Google, they’re not showing it: previous Cyanogen investors including Benchmark Capital and Redpoint Ventures also invested in this round, as did Chinese tech giant Tencent. In a blog post accompanying the announcement, Levine likens Cyanogen to Linux Red Hat or Windows — operating systems that thrived by being independent of hardware. “Software is eating the world, Android is eating mobile, and we think Cyanogen only just finished their appetizer and is moving onto the entree,” he says. But Red Hat may be a telling example — consumers’ appetite for it never matched its makers’ ambitions, and it ultimately pivoted into an enterprise offering. If Cyanogen doesn’t become easier to use, that entrée may prove to be out of reach.