Patching my guitar amp's firmware
4 hours ago
- #firmware hacking
- #guitar amp
- #reverse engineering
- The author reverse-engineered their Yamaha THR10c guitar amp firmware to enable speaker simulation toggling and internal speaker activation with headphones connected.
- They identified UART and JTAG headers on the main PCB, soldered connectors, and used an FT2232H-based JTAG adapter to interface with the amp's ARM7TDMI-S core.
- Using OpenOCD and GDB, they dumped the firmware, analyzed it with Ghidra, identified memory layouts, and discovered bootloader and main firmware images.
- They created tools to patch the firmware, added custom code sections, and implemented features by intercepting functions like control_set_speaker and dsp_command.
- The author also discovered a MIDI SysEx method for firmware updates, allowing others to apply modifications without hardware changes.