Hi,

Some time ago, I was involved in a legacy BIOS reverse engineering project, and I noticed that most of the analysis being made was static in nature. Essentially, we were reading the ROM binary using various tools and trying to make sense of it in our heads. However, this approach had some limitations since we didn't have access to the contents of registers, memory, etc. at any given point in the code. This made the whole process more complicated than it needed to be.

That's when I decided to develop my own debugger. I created BREAD, a compact injectable debugger that takes up only ~1.5kB of space. With BREAD, you can easily add it to the BIOS ROM and start debugging from there. Additionally, since it was designed for real mode, it can be used to debug bootable code or even DOS programs. It operates on real hardware and communicates via serial port with the GDB that you're already familiar with.