NVIDIA announces the availability of version 21.7 of L4T for the Jetson TK1 Development Kit, and version L4T 28.2.1 for the Jetson TX2/TX2i Development Kits.
The L4T 21.7 software maintenance release for the Jetson TK1 is available at: https://developer.nvidia.com/linux-tegra-r217 There are a couple of useful bug fixes.
For the Jetson TX2/TX2i Development Kits, there is a new maintenance release of L4T, 28.2.1. There are several bug fixes, plus the source code for Cboot is made publicly available. Here are the L4T 28.2.1 release notes: https://developer.download.nvidia.com/embedded/L4T/r28_Release_v2.1/Tegra_Linux_Driver_Package_Release_Notes_R28.2.1.pdf
The Jetson TX1 remains at L4T version 28.2.
In order to install the new release of L4T 28.2.1, use the new version of JetPack, version 3.2.1.
JetPack Download and Install
Here are the instructions to download and Install JetPack: https://docs.nvidia.com/jetpack-l4t/index.html#jetpack/3.2.1/install.htm
JetPack 3.2.1 release notes: https://developer.nvidia.com/embedded/jetpack-notes
Good luck on your new installs!