Disclosure: It's been quite some delay between writing this text and actually posting it. A year and a half or so. Given that I could have written an identical post yet a year prior to that, when installing the SDK my first time, I simply assume these are perpetually true and still relevant facts.
As told in an earlier post, I am a happy owner of a Garmin watch. A great thing possible to create is a custom custom watch face to use with them. In order to do so, one needs to go through the horrible experience of installing ConnectIQ SDK. This blog post is an attempt to jot down some important reminders of unexpected quirks related to that process.
It seems Garmin's releases are built against outdated legacy versions of Ubuntu. Unless you wish to end up in dependency hell, dealing with ABI incompatibilities and such, follow this simple rule of thumb; Install a virtual machine with the latest obsoleted Ubuntu LTS. The current LTS release will typically be too new to work. Please note that this tends to be true even for freshly released versions of ConnectIQ SDK. Do not even consider trying with some other distribution than Ubuntu. The SDK is expecting shared libraries with very specific versions.
At least on one occasion the download link wouldn't appear for me in Firefox, so to save some trouble one might consider to install Google Chrome.
For the actual the installation process, please see some other source. For example, Harald's Random Stuff might be a good post to read next.