dcunlocker can open FRP.
https://www.dc-unlocker.com/
I managed to restore my device.
if you used unlocker for the FRP.
after redoing the bootloader code.
install TWRP.
https://mega.nz/#!c1tyRL7Z!r3fhcK5eNHR1aaN_s8OwafD1eQutvpc2cF-lG4guQdk
restore my backup, restore, select all except oeminfo and product.
https://mega.nz/#F!lklADSZY!ORwYA7HAoVlkbjp03EoAkg
restarts.
you noticed that the camera starts but the sound, video, camera, theme boot-animation ..... does not work. (This is due to product twrp not restoring it properly)
took this meta_inf.zip, get product.ext4.win renamed it in product.img.
place it in the meta-inf zip.
https://xdaforums.com/showpost.php?p=75259927&postcount=452
reboot.
from twrp, install meta-inf.zip.
returned to twrp.
wipe / data format.
install supersu ante0
https://mega.nz/#!BgVwGILJ!PGq_3cupAyO4n66RLIGMq-V13yKOVqHzacUxwd5m5fw
reboot.
restart in twrp.
install publiczip file from ante0. to repair theme.
https://www.dropbox.com/s/6r1we6xf2dkk0qp/hw_public_rne-l21.zip?dl=0
reboot.
we now cover.
to restore the device to the origin.
twrp, restore bootext4.win that I did before being root.
https://mega.nz/#F!5gl3nDzL!N8pPmT05mnWfnYyXoZFExA
restarts.
now, with adb flash recovery.img stock.
https://mega.nz/#!EhkCQSCT!Pk7K-JHhn3bT_U5figB-6FdIh-VOwbBK8PpDjHAb15U
then you could also lock the bootloader code.
he will reset himself. and restart all clean.
édit
ah, I forgot to say.
that you will remain dolbyatmos and viper. they are in my original backup.
no problem they are not annoying.
if you wanted to use them. (be root and install the permissive mode selinux)
https://mega.nz/#F!FsUHnTbb!5J0nMtCuXIhSMzxXBOD-wQ
or delete them, be root, and with a file explorer delete them system / priv-app /.
sorry for you.
I know that I spent two days understanding everything and finding a simple solution.
I am convinced that we can do even better, but here I am tired.