ASUS has released the Android 4.2.1 Jelly Bean update for it's Transformer Pad 300 (3G model).

A quick recap, the ASUS Transformer Pad 300 is a tablet with a keyboard dock, and a pretty good one at that. Released back in 2012, the Transformer Pad had originally launched with the then popular Android 4.0 Ice Cream Sandwich. Under the hood is a quad core nVidia Tegra 3 chipset clocked at 1.2 GHz accompanied by 1 GB of DDR2 RAM. There's a rather large (for a tablet) 8 MP camera sensor at the back and a 1.2 MP front facing camera above the 10.1 inch 1280×800 IPS display. 

The good folks at ASUS have been releasing Android 4.2 Jelly Bean updates for their products since March of this year and the next product in line to receive the update is the 3G model of the Transformer Pad 300. Although this update isn't the latest 4.2.2 version, there isn't much difference anyway. ASUS has already begun the rollout of this update, but impatient owners can download the full ROM (which weighs in at about 450 MB) from ASUS's website and flash it on their device right away.

Source: Transformer Forums