3.13.0-128.177) is not available, but a newer one is (3.13.0-166.216). We redirected you there.
/usr/share/qemu/ppc_rom.bin is in qemu-system-ppc 1:2.5+dfsg-5ubuntu10.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/qemu/../openhackware/ppc_rom.bin