The time has come for OnePlue One owners to get a taste of the latest version of Lollipop. Cyanogen OS 12.1, which comes with Android 5.1.1, is now heading out to devices. Though, the rollout is starting off small, with only 2% of users getting the goods.

This will upgrade your device to Cyanogen OS 12.1, based on Android 5.1.1, Lollipop.

This update provides critical security fixes for your device to address recently publicized vulnerabilities on Android devices. As this is a sizable update, please allocate 20 minutes for the installation process and ensure your device is fully charged before proceeding with the install.

Fortunately, you don't have to wait if you don't want to. The full update is available to download (edit: see new link at the bottom of this post). It's 645MB and will work regardless of which version you have installed. This will leave your device running build YOG4PAS1N0.

UPDATE: 2015/08/25 1:56pm PDT BY

This update appears to have activated the home button in Chrome. Interestingly, the home page has been set to Bing. You know, because Cyanogen and Microsoft are such good buddies these days.

If, however, you're on the most recent release with Android 5.0, you can download the OTA that, at 304MB, is only half the size. This link right here (edit: keep scrolling) will save you some time.

UPDATE: 2015/08/26 11:21am PDT BY

After rolling out the update to just 2% of users, OnePlus has since pulled the OTA entirely due to issues it hasn't yet explained. On the positive side, those who want the update can still install manually. Just be careful not to flash with encryption.

Here are a few more screenshots from Cyanogen OS 12.1, including the new dialer with optional truecaller integration.

UPDATE: 2015/08/26 11:47am PDT BY

Aaaaaaand it's back. Here's the updated link for the new full size ROM. Also, there is a fastboot image if you'd like that. And here's the incremental update. The build remains YOG4PAS1N0.

Source: Big Update, Smaller Update