*The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.
why is my zte avail z990 stuck on bootloop after updating the phone and tried factory reset and it wont work and wont show on computer and i think but dont knw its rooted
Be aware that a factory reset does not actually "reset" anything, aside from formatting the /data (user data) partition. Contrary to common misconception, factory reset does not have any ability to fix or rollback the OS. So if something went wrong with the OS update itself (incomplete or corrupt update file, etc.), a factory reset isn't going to help.
How do you not know if its rooted or not? Unless you obtained it used, its either unrooted (stock), or you must have taken steps to root it. And if you attempted to root, there are various simple ways to verify.
Its a rule of thumb for modding phones, that you should never never never install an OTA update on a rooted/modded phone; unless you know from other sources that it is okay. This in itself may be the reason why the phone won't boot. But if you don't even know the status of the phone, its impossible to know what the cause is.
You might check out the ZTE support page, as there is a Software Update Tool under the heading "Software Updates":