Depois de muito procurar encontrei isto:
Upgrade/Update Alcatel OT-983 to 4.3 Jelly Bean1. Install the ROM Manager on your Alcatel OT-983. Get it from Google Play Store, then install the clockwork mod recovery.
2. Connect your Alcatel OT-983 to your PC employing the USB information cable. Copy the “Alcatel OT-983_4.3 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 ”Alcatel OT-983_4.3 Jelly Bean.zip” file and follow the directions for installing Android 4.3 Jelly Bean on your Alcatel OT-983. As soon as the installation is over, just reboot your Alcatel OT-983 device, and here you go, you’ve just upgraded it to the new Android 4.3 Jelly BeanThank you for visitingUpgrade/Update Alcatel OT-983 to 4.3 Jelly Bean
Note : Here Is Link To Download the ROM/Zip File : http://adf.ly/QIdiI
Este passo do rom manager parece seguro pois ja ha relatos no xda developers. Mas em relaçao ha rom sera seguro e de confiança?