Where can I get the factory firmware from?

https://www.google.com/search?q=update+the+operating+system+on+mediatek+android+tablet

How to Upgrade mediatek android tablet firmware 2022?

http://gofirmware.com > content > mediatek-android-ta...
Upgrade to newest version firmware on you device, mediatek android tablet firmware update you current version firmware to latest version, download .

How to Update an Android Tablet - Lifewire

https://www.lifewire.com > Tablets > Android
Mar 19, 2021 - Manually check for updates by going to Settings > Software Update > Download and install. Android tablets automatically update periodically ...

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Your tablet's firmware has been modified with aftermarket software. (users typically do this to gain "root" access on the tablet.) If the software will not load, you will need to either load the factory firmware, or try another aftermarket firmware.

Look on the back, or sides of your tablet. You are looking for a little reset button, you will need a paper clip,,this should take you back original factory reset screen

This might be what you are looking for..
How to unlock:
http://southerntelecom.com/polaroidsupport/firmware/firmware_guide_ptab8000.html
How to root for google apps:
http://forum.xda-developers.com/showthread.php?t=2066041

If you need further help, I’m available over the phone at https://www.6ya.com/expert/michael_e0539de310ea5ad7

hi Akram.
this is all i could find out.
When the tablet is turned off, keep home button pressed.
Now turn on tablet while still holding the home button.
When white android figure appears, release both buttons.
You will get into recovery mode, you can select "restore factory settings" there.
Download the right firmware here: ONDA

Extract the content to the root of your sd card (since you cannot use your tablet, i suggest using a cardreader + pc or another tablet? or try to hook your tablet to the pc and hope it recognizes it)

There should be 5-6 files now on your SD card.

Turn on tablet while holding home button, untill white android figure appears then release.
It should update your firmware now...
or you could try this link on how to do a hard reset.
but do so at your own risk.
Onda V811 hard reset format factory mod recovery rom install ..
or try this link for more info.
hard reset tablet onda v811 Google Search
or this one.
811 Onda Tablet logo screen white Google Search

contact sunrex (vitalasc) via email. They will put all the files to completely start over with stock firmware in your dropbox. You will need to open a dropbox account and they will put everything you need in it. They did it for me and it worked flawless. The tablet is old and slow, but it is rooted from factory, you can overclock a bit to gain a little performance. Looking at the date of this ?, probably too late, but better late than never.

how do factory reset it