Setting up the GCC cross-compilation toolchain to make your own Ndless C/C++ programs on Linux is easy thanks to the build_toolchain.sh script of the Ndless SDK, but a bit long as everything needs to be built from scratch.
We’re now introducing the Ndless SDK Docker image. Docker is a platform to build and share applications through lightweight containers. The Ndless SDK Docker image packs the Ndless SDK and all its dependencies.
First make sure to update your Linux box to the latest version of Docker. Then run the two commands:
$ sudo docker pull ndless/ndless-sdk $ git clone https://github.com/ndless-nspire/Ndless.git
Add ndless-sdk/bin-docker/ to your PATH and here you go! All nspire-* commands will automatically be propagated to the Docker container.
[2014-08-27]: Change Docker Hub repo and GitHub repo URLs to latest.
ndlessly 
Can anyone help me fin OS 3.6 for my Nspire? my calc shut down for a while and I just got it back on, but by the time I found out Ndless 3.6 was out, TI had taken os 3.6 off the website. I have OS 3.1 right now but can’t figure out a way to download 3.6! HELP!
John, OS 3.6 is available here: http://tiplanet.org/forum/archives_list.php?cat=OS+Nspire&lang=en
Do not upgrade to OS 3.9 as you won’t be able to downgrade again.