I dumped the ROM of a Tamagotchi using the code execution ability I posted previously. I wrote 6502 code that dumped each byte of the memory space of the Tamagotchi, and output it over port A (which is usually the Tamagotchi button input) via SPI. » Natalie Silvanovich | kwartzlab.ca
On the surface, a microprocessor’s registers seem like simple storage, but not in the 8085 microprocessor. Reverse-engineering the 8085 reveals many interesting tricks that make the registers fast and compact. The picture below shows that the registers and associated control circuitry occupy a large fraction of the chip, so efficiency is important. Each bit is implemented with a surprisingly compact circuit. The instruction set is designed to make register accesses efficient. An indirection trick allows quick register exchanges. Many register operations use the unexpected but efficient data path of going through the ALU. ...
So I wanted to find out: what exactly is the bug in the program that causes this behavior and also, can it be fixed? First I looked on the Internet to see if the answer has already been found. Some good starting information is located at http://www.jeffsromhack.com/products/donkeykong_tech.htm. There, Jeff Kulczycki breaks down the math of the kill screen, showing the formula that is used to compute the bonus for each level. The formula says the level times 10, plus 40, gives the number of hundreds in the bonus timer. If the result is too large it is forced back down. The key to this is that the level number is used in the calculation. On level 22 an overflow occurs, leaving the player with just 400 points on the timer because the multiplication and addition yields a number larger than 256. ...
No Starch Press and I have decided to release this free ebook version of Hacking the Xbox in honor of Aaron Swartz. As you read this book, I hope that you’ll be reminded of how important freedom is to the hacking community and that you’ll be inclined to support the causes that Aaron believed in. I agreed to release this book for free in part because Aaron’s treatment by MIT is not unfamiliar to me. In this book, you will find the story of when I was an MIT graduate student, extracting security keys from the original Microsoft Xbox. You’ll also read about the crushing disappointment of receiving a letter from MIT legal repudiating any association with my work, effectively leaving me on my own to face Microsoft. ...
This project has been an astonishing little journey. Many of my previous projects were characterized by an amazing outpouring of effort to build something highly intricate and ultimately invisible. This is the opposite kind of project. A little bit of work and a little custom design to create something new and exciting that I can immediately use in my everyday life. It also happens to be a sex toy. In other words, I wanted to hack something I actually use: my vagina. ...