A long time ago, in a galaxy far, far away, a man named Mikhail wanted to dump the firmware of a microcontroller. He’d done this many times before with many other microcontrollers, but on this day, the microcontroller wasn’t willing to cooperate. Mikhail figured out that if he could erase part of the microcontroller’s brain, it might be a bit more willing to comply, but doing this was no small feat. With a CNC mill, powerful acids, ultraviolet light, some nail polish, and lots of ingenuity, our hero eventually perservered. This is his story.
https://duo.com/blog/microcontroller-firmware-recovery-using-invasive-analysis