Exactly, a week ago, Asus started rolling out the official Android 4.1.1 Jelly Bean update for the U.S. version of the Asus Transformer Pad 300 tablets. Today, Asus has provided full Jelly Bean firmware on its official website for the Transformer Pad TF300 users, who haven’t yet grabbed it from the sky. The Jelly Bean OTA update couldn’t be downloaded for some users due to an unlocked bootloader installation on their tablets.
The Android 4.1.1 Jelly Bean update for the Transformer Pad 300 brings new power saving options, global file search and improvements to the pre-installed apps and it wouldn’t clear any of your data. The new build number will JRO03C.
You can download the Jelly Bean update by hitting up Settings > System Firmware Update > Check Update and proceed the further on-screen instructions. Otherwise, you can download the full Jelly Bean firmware directly from the below link. keep in mind that this firmware break root and overwrite any custom recovery builds on your tablet.
Source: Asus