Depending on your specific device model, you can choose between official manufacturer updates or unofficial custom ROMs. Official Update Methods
For a manual official install, download the official firmware file (often in .tar.md5 format) and use the Odin tool on a PC while your phone is in Download Mode . Unofficial Methods (Custom ROMs) android 2.3.6 update to 4.1 download
For 99% of devices on 2.3.6, there is no official download. You must use a community-developed custom ROM like CyanogenMod 10 or AOSP 4.1. Depending on your specific device model, you can
You will need these files on your PC (Windows 7/10 recommended): Depending on your specific device model
In this 2,500+ word guide, we will explain exactly what Android 4.1 (Jelly Bean) offers, why official updates don't exist, where to find safe downloads, and how to install them step-by-step.