Every month, Google posts a new security update for the Nexus and Pixel line of devices. The Android security update for March 2018 are already live for a number of devices.
Google has posted both the OTA’s and the factory images for the selected Nexus or Pixel devices. The supported devices includes Nexus 5X, Nexus 6P, Pixel C, Pixel, Pixel 2, Pixel 2 XL and Pixel XL.
For now, we have March 2018 Security Firmware files based on Android 8.1.0 Oreo for the Pixel 2 and Pixel 2 XL (OPM1.171019.021), Pixel and Pixel XL (OPM1.171019.021), Nexus 6P (OPM3.171019.016, OPM5.171019.017), and Nexus 5X (OPM3.171019.016, OPM5.171019.017).
March 2018 Security update for the Pixel 2, Pixel 2 XL also brings Performance, Audio improvements, and other fixes.
You can grab Factory Image or OTA file at the links below.
Links: Factory Image | OTA File