Hi.
New day, new problem. My ROS hangs everytime i start new terminal (Router disconnected message pops up). I just want downgrade my ROS from 3.30 to 2.9.51. I have transported all needed npk to router with Filezilla. And now i need to set “system package downgrade” but i can’t open terminal. Same with telnet connection and putty’s. 
maybe somone knows other way to downgrade ROS without terminal. Maybe there is some script? Thanks
use winbox to downgrade the RouterOS - in system package menu there is a Downgrade button.
Ok, reason this happens? it maybe my RB can’t work with 3.30? or i must instal those system option i will use, not all, as i did. RB133c3
what packages you have installed?
Just downgrade to 2.9.51. So which npk i must instal for CPE
Just update it to 3.30 with these npk and looks fine, Maybe there is some npk i don’t need for CPE?
when free memory count to 2300KB router disconnects. can i use different npk. ect. system 3.30 and other components from 2.9.51?
Unistall NTP, Calea and User-manager.
Main reason my RB hungs and reboots is not enough memory (when free RAM memory reaches 2300KB = reboot)
yes, and this is why you needed to remove calea, user manager, ipv6, multicast, ppp, ntp, hotspot and ups 
you need only advanced tools, system, wireless and routerboard in a CPE. even advanced tools is not so necessary
Ok, i already get needed info from MT support team, but anyway thanks all. I will buy rb411ah. hope it will be much better.