Hello everyone, tell me what could be the problem.
Mikrotik RB3011UiAS r2 6.48.1
After installing the Protected RouterBOO checkbox or via the console
/system routerboard settings set protected-routerboot=enabled
The connection with Mikrotik is interrupted for a short time. After reconnecting, the checkbox is unchecked again. It's like the settings aren't being saved.

You need to power cycle the router (eg. remove power plug)
or press reset button shortly after enabling the option.
(Both are physical actions)

You need to power cycle the router (eg. remove power plug)
or press reset button shortly after enabling the option.
(Both are physical actions)

This means. Should I check the "Protected RouterBOOT" box and immediately press the reset button?

Actually apparently it is only reset button.

The following topic has some good information.
viewtopic.php?t=181158

Probably also worth reading
** edit **
https://help.mikrotik.com/docs/display/ROS/RouterBOARD
and
https://wiki.mikrotik.com/wiki/Manual:R ... bootloader

Also if very old Backup bootloader may need updating.