Dual-Boot & Android vanishing issue

[johnfreakt]

Bought a brand new Pipo X7s ( I live in the Netherlands ). First use: from the dual-boot Pipo screen, selected Android. Set my account at Google. Everything OK. Shutdown and restart. Again from the dual-boot Pipo screen, selected Windows 8, this time...
Windows ask for my language and location preferences. I choose, but immediately after, Windows setup starts. No way back ( no "cancel", no "back" button, just "next").
I see a typical Windows 8 installation ( screen is changing colors during process ). After some time, when installation was successful, my windows account is requested and my preferences are automatically imported. Windows 8 is now running, everything OK.
BUT, BIG ISSUE:
After shutdown, each time I start Pipo,
NO MORE DUAL-BOOT MENU DISPLAYED AND ONLY WINDOWS 8
... is started. This loop in Windows O.S. is from that time PERMANENT !!!

Reported this to Dutch seller, but he says he has no explanation on how this is possible because Windows was pre-installed.
He can not help to restore the dual-boot.
This is my first experience with a dual-boot (mini) pc running Android.
I experienced once that installing Windows 8 after Ubuntu will erase all non Windows O.S. and that by installing Ubuntu "next to Windows", Windows will be listed in the boot menu.
Please help me ( I do not expect help from support at pipo.cn or at the facebook pipo site ) ?

[johnfreakt]

Thanks for not welcoming me, so far.
Was hoping to get some help from experts ...
Tracy at support from Pipo.com provided an .exe fix. It is a kind of widget, named "switch OS ..." or something like that. I managed to install in Windows 8, than it shows as a widget to click inside for switching to other OS. When done, Windows will shutdown, screen will black-out, The Pipo boot screen with the distinct Pipo logo will display and Android will start.
The widget can be set to be always visible inside Windows. When done, the next reboot will display the vanished Android versus Windows dual-boot screen (with both logos) that will show briefly as it did at first use.