Last week i tried to upgrade my routers from 6.27 to 6.29.1, after this upgrade my rb2011uias-2hnd-in was bad accessible.
my winbox disconnects may times. Also Eth6 port was blinking en even when i shutting the port it was stil blinking after 1 min.In the log there was continuously the text there is a loop on eth6 even when there was nothing connect on this port.
After a few hours trying I decided to go back to 6.27 after the downgrade same problem was there 
This week a send my router back to my reseller and he send me a new one verry good service btw from wifihouse in the netherlands. Yesterday i started again with upgrading to 6.29.1 after this upgrade the rooter was freezing by booting …
i had to use the reset buton to get it working, after this ther was no loop message in the log but there was another problem, my capsman didn’t recognize RouterBOARD RB951G-2Hnd and yes they running also on 6.29.1.
After a few hours a have dowgrade everything to 6.27 it’s working fine now but when downgrading i had the same problem freezing by booting, after reset button it works fin again… but stil strange that this happens. do someone recognize problems like this ?
my hardware
1X rb2011uias-2hnd-in
2 X RouterBOARD RB951G-2Hnd