Comment # 2 on bug 968600 from Ruediger Oertel

I've updated cdra to the last release which is also two years old
and added the patch from git to the README file telling:

+CRDA is no longer needed as of kernel v4.15 since commit 007f6c5e6eb45
+("cfg80211: support loading regulatory database as firmware file") added
+support to use the kernel's firmware request API which looks for the
+firmware on /lib/firmware. Because of this CRDA is legacy software for
+older kernels. It will continue to be maintained.

crda is not meant to be called directly which explains the error -7 above.

for the error 255 I can only speculate, could be the wireless-regdb is
missing or the driver does not support the interface that crda used.

let's close this bug.