Hi, I have hopefully simple questions that I couldn't answer myself using FAQs or google: is it in general allowed to mix old and new versions of toolchain tools? Is it needed to rebuilt binary libraries (libmy.a) when upgrading toolchain version (starting from gcc 3.4.3)? For example, using arm-elf-gcc-3.4.3 and ld-2.21 or vice versa? (I made a quick check and it seems .code and .ro_data in my ELF are bitwise equal, so I think there is no problem doing this, right)? Is it allowed to link libraries compiled with different compiler versions? For example, liba.a compiled with arm-elf-gcc-3.4.3 and libb.a with 4.3.x or 4.6.x? If linking works, can I assume that the result will be valid - or - could it happen that the code links, passes first simple tests but later fails under rare circumstances? Does it make a difference when not only considering C code but also considering C++ code? oki, Steffen