The older the Nuvi, the easier the hack. The "legendary" hackable models are the Nuvi 200, 250W, 760, 780, 1300, and 1490.
On some models like the 2595 LMT, the screen locks automatically when removed from the mount to prevent accidental "pocket dialing" or button presses. Garmin Nuvi Hack
Older Nuvis officially support cards up to 4GB or 8GB. However, with a simple format hack, many can read much larger cards. The older the Nuvi, the easier the hack
Your Nuvi will now beep or show an icon when you approach specific custom locations you've added. Use a Larger MicroSD Card The older the Nuvi