I'm copy paste this tutorial from forum.xda-developers.com :The ZTE Avid 4G owners may also want to keep their device up-to-date. So we thought of giving you a tutorial of how to upgrade ZTE Avid 4G to Android 4.2 Jelly Bean. But prior to telling you how to install Android 4.2 Jelly Bean on ZTE Avid 4G, let’s see what do you want in order to be able to perform the installation. You will have to download 4.2 Jelly Bean ZTE Avid 4G port. You will also have to root your ZTE Avid 4G to prepare it for Android 4.2 Jelly Bean upgrade. Discover how to root ZTE Avid 4G and install Android 4.2 Jelly Bean from here. Here are the download links of the files you want to update ZTE Avid 4G to Android 4.2 Jelly Bean. Just before beginning to upgrade your ZTE Avid 4G to Android 4.2 Jelly Bean don’t forget to backup your information, as contacts, text messages and the apps installed from Android Marketplace Location who may be lost when the installation finishes. Now let’s see how to update ZTE Avid 4G to Android 4.2 Jelly Bean :
1. Install the ROM Manager on your ZTE Avid 4G. Get it from Android Marketplace Location, then install the clockwork mod recovery.
2. Connect your ZTE Avid 4G to your PC employing the USB information cable. Copy the “ZTE Avid 4G_4.2 Jelly Bean.zip” file you downloaded to the SD memory card.
3. Restart your device in the recovery mode using ROM Manager. As soon as in Recovery Mode, go to ROM Manager and select backup / restore to back-up your information.
4. From the Recovery Menu do a total data erase (including Delvik Cache). When completed, go back to Recovery Principal Menu and choose Flash ROM from SD Card. Navigate the location you copied the ”ZTE Avid 4G_4.2 Jelly Bean.zip” file and follow the directions for installing Android 4.2 Jelly Bean on your ZTE Avid 4G. As soon as the installation is over, just reboot your ZTE Avid 4G device, and here you go, you’ve just upgraded it to the new Android 4.2 Jelly Bean.
Note: Here Is Link To Download the ROM =
The ROM File size is 128 MB, so I split the file into 3 parts :
ROM Part 1 : http://adf.ly/ZIWPr
ROM Part 2 : http://adf.ly/ZIWVr
ROM Part 3 : http://adf.ly/ZIWfI
To combine 3 parts files above into 1 file just use WINRAR, then extract the files into ZIP format.
If any problem with the ROM, maybe because the ROM have corrupted during the download process, you can try to re-download the ROM.
Thank you for visiting Upgrade/Update ZTE Avid 4G to Android 4.2 Jelly Bean
Tutorial Video : Easy Way To Download at downloadsafe.org/sharecash.org =