Resetting CMOS/Bios Settings On Onda Tablet V891

fredprom

Junior Member
Oct 17, 2018
2
0
I have an Onda Tablet V891 Dual Boot. I've changed the Bios settings and now I think I totally bricked the tablet. Does anybody here know how to reset the Cmos? The combination Power + ESC did not work. Thanks for your help.

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Traveller

Administrator
Staff member
Jun 16, 2012
2,763
965
Bricking the UEFI (BIOS) is virtually impossible unless you do something foolish like pressing the power button down long enough to cut power to the tablet. So using a keyboard attached to the tablet you should still be able to get into the UEFI, even if you have to hammer repeatedly on a key until it tosses up an error that allows you to get in. This is vitally important, because the best way to reset the UEFI is by doing it through the UEFI menus. The alternative is taking the tablet apart and pulling both the main and backup batteries, pressing power to discharge any energy still in capacitors, then reassembling the tablet and praying you didn't kill anything.

Even if you do reset the UEFI, the internal storage may have been wiped, meaning no OS installed. If you didn't already have it, you would then need the restore media from Onda to restore both Windows 10 and Android.
 

fredprom

Junior Member
Oct 17, 2018
2
0
Bricking the UEFI (BIOS) is virtually impossible unless you do something foolish like pressing the power button down long enough to cut power to the tablet. So using a keyboard attached to the tablet you should still be able to get into the UEFI, even if you have to hammer repeatedly on a key until it tosses up an error that allows you to get in. This is vitally important, because the best way to reset the UEFI is by doing it through the UEFI menus. The alternative is taking the tablet apart and pulling both the main and backup batteries, pressing power to discharge any energy still in capacitors, then reassembling the tablet and praying you didn't kill anything.

Even if you do reset the UEFI, the internal storage may have been wiped, meaning no OS installed. If you didn't already have it, you would then need the restore media from Onda to restore both Windows 10 and Android.
Thanks. I have already opened the tablet. I've disconnected the battery already and left it disconnected for 12 hrs. Still I can't enter the Bios. Do you have an idea where the second/backup battery is located?

Sent from my GS270 plus using Tapatalk
 

Traveller

Administrator
Staff member
Jun 16, 2012
2,763
965
If you pulled out the battery that normally powers the tablet as well as the battery for the UEFI, there are no other batteries to pull. Your next thing is to look for a jumper on the motherboard that can be used to reset the UEFI.

If none of this works, you may have to call Onda.
 

Traveller

Administrator
Staff member
Jun 16, 2012
2,763
965
Don't have an Onda so I can't tell you where the jumper would be located, or even if there is a jumper.
 
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