The early 2000s saw a Cambrian Explosion of form factors for mobile devices, and one of the most feature-rich phones of the time was the Danger Hiptop, better known as the T-Mobile Sidekick. [ashe] wanted to get the phone going again, which took some sleuthing.

While not advertised as such at the time, the Hiptop was primarily a client for web apps from the Danger servers. So, when Danger was shuttered, so were most of the phone’s features. [ashe] was able to track down the SDK for the device’s Java-based OS, but to get any programs running on an actual device, they needed a developer key. After finding a few more clues, they were able to use CADO-NFS, a general number sieve, to crack the 512-bit encryption scheme for the system’s developer key and generate a new one for their device.

[ashe] ported a visual novel to their Sidekick 3 with their new key, saying “Endings arrive as real Sidekick text notifications, using an emulated modem.” Work continues on the Re:Danger server to bring other functionality back, including plans to spin up a GSM network to connect an actual Sidekick. The server replication only works with an emulated Sidekick so far. They did include a Sidekick emulator on their site if you’d like to try it yourself.

If you’re a fan of the form factor but would like something with a bit more power, we’ve seen a UMPC inspired by the Hiptop/Sidekick a few years back.