Firstly, it's the Mifare Classic Tool that I used to write hex data back to Mifare 1k card with my NFC phone - Moto X 2013. And after several steps of studies and development, I find a way to read the money data from the card and generate legal hex data then write back it to the card. And it works perfectly, which made me so happy. Seemed like I was a real hacker, can easily change the money on the card with a simple app. After that, I want to share this happiness with all guys who are interested in RFID. After about 3 weeks of development, the first version of MTools came out. Here're the things that you need to know to use it better.