Problem is in versions newer then 2.03.1 - so all previous versions (with 2.03.1) are OK. I can normally compile source code but when I try to call whatever function from assembly code in e.g. C, linker say: undefined reference to my function. I use only parameter "-f elf" so it is in ELF type. You can check this bug with my source code of own OS - ZeX/OS - git repository is here...