Over the last decade, the importance of Free/Libre/Open Source Software (FLOSS) has increased dramatically and the size and scope of the OSS conference within which this workshop takes place is testament to that reality. This volume contains the proceedings of the joint workshop: the first International Workshop on Foundations and Techniques bringing together Free/Libre/Open Source Software and Formal Methods (FLOSS-FM 2008) and the second International Workshop on Foundations and Techniques for Open Source Software Certification (OpenCert 2008). All submitted papers have been reviewed by at least 3 Program Committee members. The aim of the workshop has been to bring together researchers from academia and industry, firstly, to study the question of FLOSS certification and, secondly, to explore in the largest possible sense the question of how formal methods can be brought more successfully to bear on the open source phenomenon, and also how FLOSS can be brought more fully into the formal methods community. The organisers would like to take this opportunity to thank the contributors, the programme committee and all the referees for their interest and hard work. We leave to the reader the seeds the participants have sown.