Can I downgrade my Nexus One from Android 2.3.6 (Gingerbread) to Android 2.2 (Froyo)?
105173
Downgrade 2.3.6 to 2.2.2 - Nexus One
109018
Is there an empty/clean version of Android for tablets?
134548
How to install i386 packages on Ubuntu on ARM-based Nexus 7?
24788
Downgrading from iOS 8.1 beta 2 to iOS 8.0.2
85188
Is it possible to update any iOS 6 device to iOS 6.1.6?
32983
how to downgrade moto g 2nd gen from lollipop to kitkat without root
158331
How can I ensure reliable updates for an Android phone/device?
2136
How to roll back Ubuntu to a previous version?
22440
When will my phone get the Android 2.3 update (Gingerbread)?
13893
How do I update Android on my device?
117568
How can I check the system version of Android?
72031
Can every Android device be updated to the most recent Android version?
150473
Will I get OTA updates after installing Android L Developer preview?
5405
Can I install any iOS version I wish by picking and choosing which firmware to restore?
65680
How to distinguish Nexus 7 (2012) and Nexus 7 (2013)
85807
When will my device get the Android 4.1 update (Jelly Bean)?
31971
Can you upgrade the RAM of an Android device?