Kindle 3.1 Jailbreak

I was bored one weekend and decided to jailbreak the new Kindle firmware. It was time consuming to find bugs, but not difficult. Unlike the iPhone, the Kindle doesn’t really have security. They have a verified FS and signed updates and that’s it, but I will still call my jailbreak an “exploit” just to piss you off. Previous Kindle 3 jailbreaks worked (AFAIK, I haven’t really looked into it) by tricking the Kindle into running a custom script by redirecting a signed script using a syslink. This worked because the updater scans only “files” that do not end with “.sig” (signature files to validate the file). They fixed this now by scanning all non-directorys that do no end with “.sig”. This is the first bug I’ve exploited. Part one is getting the files into the update, which I did by conventionally renaming them to “.sig” even though they’re not signature files. Part two is harder, getting the unsigned script to run. Continue reading

Creating a PSP FreeCheat Memory Patch

FreeCheat is a memory editor and cheat device (like Action Replay) for the PSP. It includes features like a live in-game memory viewer and searcher. One of the feature that intrigued me is the memory patcher. I had no idea what it does, but I assume it does what it says: patches the memory. Problem is: I’ve searched everywhere, but there seems to be no information on how to create a FreeCheat memory patch for the PSP (only .pat files for Monster Hunter). Well, it’s not that hard. After some trial and error, I’ve found out how to create a FreeCheat .pat memory patch. Note that the following should only be attempted by a person with enough technical knowledge to understand it. Continue reading

Ajax Word Search Solver

I almost forgot about this.

This project was written purely out of my boredom in class. I wanted to learn 1) Javascript, 2) jQuery, 3) JSON, and 4) more Ajax, so I decided to write this simple word search solver. The “backend” (puzzle solving algorithm) is written in PHP not because I didn’t know how to write it in Javascript (ok, maybe it’s because of that),  but because I wanted to try out JSON by allowing PHP to pass the puzzle solutions to Javascript. This word search solver has features such as: solving the puzzle live by highlighting the solution as you type, adding lists of words, removing words from list with delete key or double click, etc.

It’s also very buggy, because as I stated, I wrote this in a few hours with zero knowledge of jQuery/Javascript.

Anyways, here’s the site: http://yifan.lu/wss/ and the source: http://yifan.lu/p/wss