Prototyping boards based on modern Field Programmable Gate Array (FPGA) are ideal for teaching practice in digital design. The use of these prototyping boards in schools of engineering and technology allows the development of complex digital systems that enhances the ability of the students to address real-world problems. Nowadays, by means of virtual laboratories, students can verify remotely their designs overcoming laboratory limitations in equipment, personnel and space. However, most of the available tools for remote verification checks the design via webcam. On-chip debugging requires pattern-based verification in a similar manner as a simulation stage. This paper presents an open-source tool, called ccLAB, for pattern-based remote verification of FPGA-based circuits. This tool is suitable for efficient sharing based-FPGA prototyping boards in virtual laboratories.