Relock Bootloader without flshing stock zip(i already have stock Nougat 7.0)

[cooldude1598]

I was updating my system security patch from official moto but after restarting it started twrp and asked me if i want to flash that update file, after swiping it opened Twrp homepage(i was unable to restart from its reboot option but i went to the bootloader and started cell (Working correctly currently))
Two Options
1. I should lock the bootloader
2. Leave it as it is.

If option 1. lock my bootloader on stock Android Nougat 7.0 on Moto G4 plus Athene XT1643. As i have stock android and precious data so i only want to lock bootloader Without wiping my system Data (I can wipe if no other way is available).
For option 2. Keep it as it is.

Please suggest me what to do and how?
And tell me about official Oreo or Custom Oreo(best option)
Sorry for my bad English and errors(If any).
Thanks in advance

 

[____Mdd]

@cooldude1598 official update can not be flashed through TWRP, you need to have stock recovery and unmodified system/kernel/etc as well.
If you have played with stock ROM (flashed custom kernel/ rooting / installing and flashing other stuff ), it will fail through stock recovery too, for that you need to download appropriate stock ROM according to your current version of stock ROM, and it will erase everything (includes apps and app data, photos, videos and anything on internal storage)

you said, you have system data ?
What is that?
If it is photos, videos, or personal data then move it to external sd card or PC, apps and app-data can be backup through titanium backup, and also move it to safe place.
If not this, then tell us what system data?

Fro another question about LOCKING, it is not necessary to re-lock bootloader, you can go with unlocked bootloader, don't lock again, once you flash stock ROM through fastboot, you can update to any security updates without fail.

English is weak here too, hope you got it what i said.