Ok, we fixed the error some days ago, but I forgot that it's still present on the latest public firmware.
To fix the issue, type this command first:
mount none -t tmpfs /root
Gcov/gprof are for glibc only, so you can't use those. But oprofile is just as powerful, and I'd even say it's better since you can profile the entire system: your program, the libs it uses, and the kernel. The only requirement for the program to profile is that you compile it with the -g flag, and that you don't strip the binary; you can profile it with the regular CFLAGS without problems.