This is a tutorial that i have done  on my meizu note 9 who had problems with mobile data LTE signal and other bugs.  Hope is useful for some one of you.
Please follow instructions. First of all
1.inserts sim card
2.Do a factory reset with wipe data from settings.-Storage and backup-Factory data reset-check both (reset phone..and format data..) then start resseting.
3.After phone booted succesfully power off.
5. Donwload through pc latest rom update. Zip.  At the moment
7.2.2 global
6. Boot the phone on recovery mode. Press Vol+  and power button till meizu logo.
7. Connect phone with comp.  Copy downloaded zip file on root of your phone memmory.
8. On the recovery menu check both options and  start upgrading. Please in this stage do not unplug cable and do not  touch  anything.  Phone will boot normally then unplug from comp. do the initial menu config. Of your meizu.

This tutorial is for my case problem and for other software problems or bugs that the fresh meizu note 9 could have

If any of you have again LTE signal problem or any signal problem please do this step.
Dial. *#*#4636#*#*
Meny compare.  Go to phone and there is some option there where you can choose between bands configuration. For europe please choose latest option.  For other countres please inform with your sim card operator.