Open Source Firmware Conference 2025

Debugging techniques using Slim Bootloader

Debugging is a crucial aspect of firmware development, particularly when bringing up a new platform or when developing a new feature. However, debugging firmware is challenging because of lack of rich debugging environments typically found in operating system-based systems. Effective debugging not only aids in identifying and rectifying errors but also enhances the overall quality, reliability, and performance of the system.

Slim Bootloader supports various debugging techniques and this presentation will delve into a suite of advanced debugging methodologies tailored for SBL, providing developers with a comprehensive toolkit to address and resolve issues during the development phase.

We will explore the following techniques:
1. Tracing/Debug Logging: Enabling detailed logging mechanisms to capture and analyze system behavior, facilitating the identification of anomalies and errors.
2. Post Code via Port 80 LED Display: Utilizing hardware indicators to convey system status and error codes, offering a straightforward method for real-time monitoring and diagnostics.
3. Bootloader Shell Interface Utilization: Leveraging command-line interfaces to interact with the system, enabling direct manipulation and examination of system registers, memory and configurations.
4. Source-Level Debugging with Hardware and Software Tools: Employing sophisticated debugging tools to inspect and modify source code, providing deep insights into system operations and facilitating precise error correction.
5. Python-Based Automated Debugging and Triage Tool: Introducing a Python-driven solution designed to automatically diagnose and identify the location in code causing specific issues, streamlining the debugging process and enhancing efficiency.

Depending on the complexity and nature of the encountered issue, developers can opt for one or a combination of these methods to effectively debug and resolve problems. This presentation aims to equip participants with the knowledge and skills necessary to leverage these techniques, ultimately fostering a more robust and reliable Slim Bootloader development environment.