How to factory reset 7.1 octocore

[goler]

Settings>Car settings>Reset factory

The 'reset factory' option pops up a message saying

If you restore factory mode, the third-party softwares will be ...

I tried 'lost', nothing happened.

What is the secret answer to enable a factory reset ?

[Jammy]

Hi,
please first tell me your order number in amazon or buyer id in ebay,Pumpkin or AliExpress so that we can confirm more information about your unit and provide you positive solutions.
I don't suggest you restore the unit to factory settings,because this will lost many app including some original app.What the trouble you suffered?
Regards

[goler]

I want to reset the unit before I return it.

The reset code is in the manual so I don't need it now. Thanks.