This could be an artifact of the -j64 (BTW, has anyone else noticed the makefiles can only keep 5 or 6 cpus busy at a time much of the time, and often less?).

There are probably still bugs in our build system w.r.t. make -jN. I occasionally use it to build the compiler, but rarely any other parts of the system. What exactly are you trying to use -ffunction-sections for? I'm pretty sure it won't work as things stand currently, unless you can guarantee to be able to find a text/data boundary symbol for the garbage collector (currently it has to be able to distinguish text from data, we're in the process of lifting the restriction but it's a lot of work). Cheers, Simon