Upgraded from 4.2 to 4.3 to check out the spectrum analyzer on my RB433. After reboot I am now experiencing intermittent ethernet connectivity on all three ports. Cannot MAC Telnet. Cannot access the device.
How can I downgrade without losing the config?
Thanks
U can’t access RB through winbox, IP telnet? I would recommend u to use Netinstall. But if u are able to access your RB through console, telnet or winbox, just use command [admin@Mikrotik] >system package downgrade
I finally got it to downgrade via the serial console. This probably would have worked from the beginning, but I could not connect to the router using the standard 115200 8N1 console config.
Ended up working at 2400 8N1 - go figure. Not sure what sparked me to try this…
I had another RB433 that I had put 4.3 on and was able to MAC Winbox into it from Ether1 only. This however was not the case with the 2nd unit that I put 4.3 on.
By the way, my R52H wifi interface was working fine on 4.3 - but because of the way I have my router configured and locked down, I was unable to access any of the mgmt features. 
Guess this was a good test of the security I had setup.
Hope this post helps someone else with the same issues.
I used 4.3 and downgrade to 3.30. Evrybody says 3.30 is the more stable
There was a bug in 4.3 with regards to RB433 boards. Rather downgrade to 4.2 or upgrade to 4.4 (the latter works just fine).