During July 2025, Michal Mnich focused on improving file system reliability in the koreader/koreader repository by addressing cross-device filename compatibility issues. He developed and delivered a targeted bug fix in Lua that sanitized vFAT filenames, replacing invalid characters with underscores and trimming problematic trailing spaces and dots. This solution enhanced file and directory creation on devices like Kobo, reducing user-reported errors related to file handling. Michal applied his skills in bug fixing, file system handling, and string manipulation to implement defensive file I/O practices, contributing to overall code quality and stability. The work demonstrated careful attention to interoperability and user experience.