A method for decompressing a signalling message in a communications device in a communication system comprising the steps of receiving a virtual machine bytecode block for carrying out decompression on the signalling message; detecting in at least one part of the virtual machine bytecode block at least one predefined code block, matching the virtual machine bytecode block comprising at least one detected code blocks against a bytecode reference block comprising a reference to at least one instruction set; selecting the at least one instruction set on the basis on the matching step; and performing the selected at least one instruction set.