RC3 seems okay on Archer A6 v3 (US)

[Nathan Lutchansky]

Since specific feedback was requested on this hardware --

I've been running our household on four Archer A6 v3 units in AP-only mode 
for the past week, and it seems solid.  Initially on Petr's RC2 spins, but 
since yesterday on official RC3.

Flashing from factory to RC2 went without any problems on the first four 
units, and I just flashed a new factory-fresh unit directly to RC3 without 
issue.  Also, `sysupgrade -n` on the first four units from RC2 to RC3 
worked fine.

Boot, reboot work reliably and do not have any unexpected delays or 
errors.  Even `halt` works and appears to successfully soft-poweroff the 
device.

All Ethernet ports (lan1-4, wan) work at 1Gbps and have the expected 
labels.  I've been using VLAN filtering over the DSA bridge successfully. 
The only problems I've encountered in this area are LuCI quirks that I 
will report separately.

2.4Ghz and 5Ghz radios work more or less okay.  The only issues I've 
encountered are reminiscent of my experience with the EAP235-Wall (lack of 
DFS; timeouts after repeated configuration changes, particularly when 
unsupported frequencies are selected) so I'm pretty sure they're mt76 
issues rather than anything specific to this board.  Once a supported 
configuration is up and running, it's been solid.

Untested: serial header, LED configuration, wireless security other than 
WPA2-PSK, recovery from bootloader.

If there's anything else that would be helpful for me to test with this 
board in particular, let me know.  I'm saving a sixth unit in the 
shrink-wrap in case it would be helpful to test flashing from factory 
prior to release.

Power is the usual 12v center-positive 5.5mm x 2.1mm barrel connector. 
Pretty nice hardware for 50 bucks.  -Nathan

Tested-by: Nathan Lutchansky <lutchann at litech.org>