--- title: "[WIZnet-PICO-C example] W55RP20-EVB-PICO Firmware Not Booting After Building" url: "https://maker.wiznet.io/forum/15749" markdown_url: "https://maker.wiznet.io/forum/15749/md" type: "Forum topic" category: "General" author: "Aimee0" created: "2025-06-05T13:23:50+09:00" last_activity: "2025-06-05T13:23:50+09:00" language: "en" views: 6 replies: 0 source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)" --- # [WIZnet-PICO-C example] W55RP20-EVB-PICO Firmware Not Booting After Building ## Question Asked by Aimee0 on 2025-06-05 in General. ### **🔧 Issue: W55RP20-EVB-PICO Firmware Not Booting After Building** **Problem Phenomenon (The issue):** - After building and flashing the firmware for the W55RP20-EVB-PICO board using the specified repository, the board fails to boot up. The firmware file (`firmware.uf2`) is generated successfully, but the board does not operate as expected once flashed. **Cause (The cause of the issue):** - The issue arises because the repository in question uses Pico-SDK version 1.5.0, which does not support the necessary clock initialization changes that are required for the board to function correctly. There is a known patch (`0001_pico_sdk_clocks.patch`) that addresses similar issues, but it is designed to work with Pico-SDK 2.0.0. Consequently, the lack of support for the required changes in version 1.5.0 leads to the board's failure to boot. **Solution (Concrete code changes, configuration changes, step-by-step actions, etc., that actually solved the problem):** - Two potential solutions are suggested: 1. Update the repository to use Pico-SDK 2.0.0, which is compatible with the existing patch and should resolve the clock initialization issue. 2. Develop and provide a new patch that works with Pico-SDK 1.5.0 to address the clock initialization issue. - Additionally, there is an ongoing pull request for MicroPython W55RP20-EVB-PICO that supports Pico-SDK 2.0.0, which can be referred to for guidance. However, caution is advised as this PR is still in progress and may be subject to further changes. [View GitHub Issue](https://github.com/WIZnet-ioNIC/WIZnet-PICO-C/issues/4) --- Source: https://maker.wiznet.io/forum/15749