Hi,
i successfully installed the openwrt 21.02.2 recommend from
https://openwrt.org/toh/kingston/mlwg2
worked with no problem, connected by lan and activated wifi.
Then i changed by ssh the ip /etc/config -> vi network from 192.168.1.1 to 192.168.1.2 as usual.
Then i entered reboot
But now the blue light is steady but no connection by lan possible, neither wlan.
Is this normal?
Now i can only try connection by serial or?
Reset i tried seemed to have no effect really 
Is this the only router in the house?
Try using Failsafe Mode -
according to wiki openwrt of mlwg2 there is only the way to open it and doing serial flash.
How to do failsafe?
The device seems not operate correct and not responding to "reset" switch either
https://github-wiki-see.page/m/gmacario/kingston-mlwg2-hack/wiki/Testing-OpenWrt-on-MLWG2
The link was given to you above...
then i guess i have to open it and use serial,
there is no blinking at all, as described in the wiki about failsafe.
Also in my link provided only serial is mentioned to work.
Sounds like the next step.