Currently there are factory images available for the Nexus 4, Nexus 5, Nexus 6, Nexus 7 2012 (Wifi and 3G), Nexus 7 2013 (Wifi and LTE), Nexus 10 and even Nexus Player — but we're still waiting on the Nexus 9, sadly.
As we reported earlier, Android 5.1 brings support for multiple SIMs and cross-platform HD Voice, along with Device Protection which ties your Android device to your Google account and prevents unwanted access to your device even if it goes through a factory reset. Additionally, there are some tweaks to quick settings for easier control over Bluetooth and WiFi network switching.
Nexus 4 Android 5.1 factory image link
- Nexus 4 LMY47O
Nexus 5 Android 5.1 factory image link
- Nexus 5 LMY47I
Nexus 6 Android 5.1 factory image link
- Nexus 6 LMY47I
Nexus 7 (2012) Android 5.1 factory image links
- Nexus 7 (2012 Wifi) LMY47D
- Nexus 7 (2012 Wifi) LMY47V
- Nexus 7 (2012 3G) LMY47D
Nexus 7 (2013) Android 5.1 factory image links
- Nexus 7 (2013 Wifi) LMY47O
- Nexus 7 (2013 Wifi) LMY47V
- Nexus 7 (2013 LTE) LMY47O
- Nexus 7 (2013 Wifi) LMY48G
Nexus 9 Android 5.1.1 factory image link
- Nexus 9 (Wifi) LMY47X
Nexus 10 Android 5.1 factory image links
- Nexus 10 LMY47D
- Nexus 10 LMY47V
Nexus Player Android 5.1 factory image link
- Nexus Player LMY47V
Source: Google
