Actually I should have posted this tutorial a month ago but somehow I missed it then. I am not even sure if there is a place for such a guide but I am still doing it at the request of an user. If you remember, I published an easy guide on how to update rooted Verizon Galaxy S3 with official OTA update package without loosing root, CWM and unlocked bootloader.
Today there is another post that is meant for those who have not rooted their Verizon Galaxy S3 SCH-I535 and wish to update the firmware of their phone manually. Below you can choose the appropriate OTA update zip depending on your current firmware version. If your phone’s firmware is on Android 4.0.4 ICS, install the 4.1.1 OTA update package first then you can upgrade to 4.1.2. In case your device shows has 4.1.1 currently. you can directly install the 4.1.2 OTA package. To check your current firmware version, go to Settings> About.
If you wish to install the complete Android 4.1.2 firmware on your Verizon S3 in place of the OTA package, download the firmware from below and install it using ODIN.
Do not try to install the OTA packages to downgrade your phone’s firmware. If you wish to do that, download the full firmware file from below and use this tutorial for downgrading.
SCH-I535-VZW-I535VRBMB1-1360821900.zip (770.7 MB)
To install the full firmware, use the our easy tutorial.
If you got a rooted device, you can still update your phone’s firmware to official JB without losing root. See the guide here.
When your Galaxy S3 boots up, it should have the newly upgraded firmware. You can verify it from Settings> About.
In case your device is stuck on the boot animation after installing the OTA update package or full firmware, follow the Steps 10-14 given on this tutorial.
If you wish to root your Verizon SCH-I535 and install a good custom ROM on it for better performance and battery life, head over to the following articles.