5 years ago, one of my colleagues developed a project upon 8051 platform. Unfortunately, there was a fatal bug in the firmware which would lead to a business fiasco and damage company's goodwill. Our boss asked us if there was any means to save the business and escape from the crisis. I knew that the microcontroller' intermal memory was actually using OTP (One Time Programming) EPROM technology, so I promised to study the code and try to hack it.