In the last three weeks, wireless-regdb has failed to build 4 times on
armhf, although after restarting, the same derivations have later been
built successfully.  The last two failures were for the following
derivation, which finally succeeded on the third try:

  http://hydra.gnu.org:3000/build/862624#tabs-buildsteps

All of the failures I've seen are the same.  During the install phase:

--8<---------------cut here---------------start------------->8---
install -m 644 -t //gnu/store/5l3wmhwaq5q01ikbz4vam6ss6i8cj0lk-wireless-regdb-2015.04.06/lib/crda/ regulatory.bin
install: cannot stat ?regulatory.bin?: No such file or directory
Makefile:101: recipe for target 'install' failed
make: *** [install] Error 1
phase `install' failed after 0.2 seconds
--8<---------------cut here---------------end--------------->8---

Below, I've attached the complete build log for the most recent failure.
I have logs from three other failures as well.

      Mark