Egbert Jan van den Bussche wrote: > ../../gcc/config/avr/libgcc.S: Assembler messages: > ../../gcc/config/avr/libgcc.S:280: Error: illegal opcode movw for mcu avr3 > ../../gcc/config/avr/libgcc.S:282: Error: illegal opcode movw for mcu avr3 The errors are from the assembler, not from gcc. You might try updating to the latest version of binutils (which contains the assembler) which might have updated or fixed AVR support. Brian