Atheros onboard AR9271 can't load firmware most of the time

["Thomas Mueller" <mueller6724%bellsouth.net@localhost>]

I have MSI Z77 MPOWER motherboard, which includes Atheros AR9271 wi-fi chip, 
USB interface but part of the motherboard and not removable.

I have USB-stick installations of NetBSD-current amd64  and i386, now at 
6.99.40.

A problem now and in the past is that the firmware fails to load most of the 
time.  

I get message, near the end of /var/run/dmesg.boot :

athn0: could not load firmware (35)

I looked through source-code files but could not fine what error 35 was, like 
finding a needle in the haystack.

I see through various device man pages that some firmwares are supposed to be 
in /etc/firmware, and some are supposed to be in /libdata/firmware.  Why can't 
they all be in one or the other?

Firmware was installed to /libdata/firmware, so I made a symbolic link 
/etc/firmware to /libdata/firmware.

Is there any way to load firmware other than by rebooting?  OpenBSD has 
fw_update.

I checked against the Live USB OpenBSD 5.4 with cmp, and athn-ar9271 files 
matched, though I have never run wi-fi from OpenBSD.  Live USB website is 
liveusb-openbsd.sourceforge.net .

Tom