is my concept correct:
i noted that my main booter is corrupted and i want to switch over to backup loader.
for this purpose , the only thing to do is
1.
/system routerboard settings set force-backup-booter=yes
2.
system reboot yes
and then will run on backup mode.
is that correct?
You signature is outdated. http://forum.mikrotik.com/t/password-pin-and-and-hash/144676/1
On your question: https://help.mikrotik.com/docs/display/ROS/RouterBOARD
If to use the backup RouterBOOT. This is only useful if the main loader has become corrupted somehow and cannot be fixed. So that you don’t have to boot the device with a pushed reset button (which loads backup loader), you can use this setting to load it every time
yes - backup loader will be used always
no - main booter will be used
i did check wiki, thats why im asking here, i can tick this box and..how can i check whether im running on main or backup.
it is switching to backup by reboothing..or how that works.
There is indeed no way to see which version of boot you’re using in backup mode. You can look at the factory firmware and then deduct that the backup boot has the same version. This should be valid since Mikrotik synced the version numbers of the boot/firmware and the RouterOS version.
Your are right by assuming the the boot only is loaded when the device is booted or rebooted.
I never did this, or used it, so I am winging this from the Wiki and help pages. 
Thanks msatter
that is in production, so i’m wondering shall i follow with my assuming, or shall i wait for someone to give more tips…
sindy , what you saying ? 
The bootloader is used only at boot time, so none of the two will get used until you actually reboot the device.
Based on what have you concluded that the main bootloader is faulty? You could not boot the device except if you forced use of the backup bootloader by connecting power while holding the reset pushbutton? If so, setting force-backup-booter to yes is a safe choice; if not, I’d test that the backup bootloader really works before applying that setting, by forcing its use the above way.
A corrupt main bootloader should get fixed by a firmware upgrade (but this is also a conclusion from reading the manual, I’ve never needed that). So you may need a downgrade followed by a firmware “upgrade” (which I haven’t tried, maybe it doesn’t work) and then an upgrade back to the current version, again followed by firmware upgrade. If this doesn’t work, only netinstall can help.
@sindy i got MikroTik SXT Lite5.
Based on what have you concluded…
by default “force-backup-boot” is disabled.
I’m going to enable and reboot it, and see what is happened