Modern swarm and modular robotic systems can be composed of diverse and miniature hardware components. To deal with heterogeneity, researchers adopt a virtual machine (VM)-based approach to ease software programming and updating for robotic systems. However, current VM-based solutions neither consider resource-constrained devices, nor have limited capabilities. This paper introduces EmSBoTScript, a tiny VM-based robotic software framework that is tailored for heterogeneous and miniature platforms. We endow EmSBoTScript with features of CPU independence, low memory footprint, concurrency and synchronization. We elaborate its programming model, script language and VM architecture to show its novelty in this paper. Implementation details and benchmark results are also provided.