I patched the kernel to remove the 1GHz setting completely. That solved a lot
of unexplained crashes and problems. Of 3 boards, ordered in a single batch,
one would run for 10 minutes at 100% cpu load at 1GHz (and then crash),
while another didn't even boot properly at 1GHz. All boards run fine at
800MHz, so until TI submits a working patch, I suggest sticking to 800MHz.