Debugging Real-Mode Bootloader in GDB (CS Changed, Symbols Broken)

When CS changes mid-execution — for example, a far jump from your bootloader’s load address into your second-stage code — GDB’s symbol resolution silently breaks. You see addresses but no names, and stepping looks like it’s into the void.

This video shows the workflow that keeps symbols valid across segment changes: explicit symbol-file loads at the new segment base, plus the add-symbol-file trick that nobody writes down in tutorials.

Related

• Blog post: real-mode bootloader debugging — the segment-symbol problem
• GitHub: NanoBoot