$(ELF): $(obj)/%: $(obj)/%.o $(LIB) FORCE
$(call if_changed,link_elf)
-$(obj)/%.srec: OBJCOPYFLAGS := -O srec
+$(obj)/%.srec: OBJCOPYFLAGS += -O srec
$(obj)/%.srec: $(obj)/% FORCE
$(call if_changed,objcopy)
-$(obj)/%.bin: OBJCOPYFLAGS := -O binary
+$(obj)/%.bin: OBJCOPYFLAGS += -O binary
$(obj)/%.bin: $(obj)/% FORCE
$(call if_changed,objcopy)