Hi All, In one of my project, we used "-melf64ppc" in makefile, but newer GCC removed this flag, so will hit compiling errors. I could not find any description in manual for this option. During googling, I found there is a similar one for x86_64 -- "elf_x86_64", and this option also does not support any more, the stackoverflow topic fix the missing "elf_x86_64" issue by simply removing it from makefile. http://stackoverflow.com/questions/10425761/kernel-compile-error-gcc-error-elf-i386-no-such-file-or-directory Then I also removed "-melf64ppc" in my project, built and run, it seems work. But I want to get detailed information for this option to convince me that simply removing "-melf64ppc"(and replaced with "-m64") is a good enough fix for this issue. Anyone knows more about "-melf64ppc"? or is there any alternative options? I also downloaded GCC source code, and search the commits that related with "-melf64ppc", but failed to get any useful information from source code.