[Android Q&A, Help & Troubleshooting] SirVer:
I recently ordered an Onda obook10 dual booting tablet (Android 5.1 +Win10) from GearBest, and received it a week (and a half) ago. It is the V5 version (9th and 10th digits of S/N). Booted into Android at first, swiped around a little, and then left it alone for when I was free. Day before, I booted into Windows, and seeing that an account was already set up, hit the factory reset option (Options: remove all personal files, normal wipe (not thorough)). It rebooted, said it was resetting, then got stuck at 5% for a half hour. I then did a hard reboot, and it starting resetting again. I repeated this a few times, with different waiting periods, but it always got stuck at 5%. I wanted to see what was going on, so I opened the OS selector menu and tried to boot into Android, but that put the device into a bootloop, and it's stayed that way since. I downloaded the recovery WinPE from their website, and tried running it; all went well until the last step (installing the install.wim file), which succeeded, but when the batch file tried to set the boot options/flags, it threw an error about not being able to access D:, and failed. Tried making the recovery USB and installing multiple times, but it failed every time. I then tried Gandalf's WinPE image, which booted, and tried using imagex to install the .wim file to C: manually, as detailed here. This failed too.

I'm at my wits' end, honestly. I have no idea what else to try. There's another WinPE file available for download, but it's dated only a couple of weeks after the one I already have, so I'm hesitant to download it if there's any other option (I have very low bandwidth, it would take me at least two days). Also, it's hosted on Baidu, and the download times out after about an hour, and cannot resume. If anyone could give me any ideas, or point me towards a guide I haven't found yet (I've read all the relevant ones I could find on the Onda forums, but please post them anyway if you think they would be helpful), that would be great.

What would be perfect is if someone could upload, or point me toward a system dump/partition clone of at least the Windows partition and boot partition; I have the tools needed to flash those.

Thanks in advance.

EDIT: I managed to fix this a while ago, and have put the procedure somewhere in this thread, but since people keep popping up every now and then asking for it, I'm going to put this here so it's easier to find. Copied from later in the thread, here, and modified to be more general:

This uses slightly modified commands from the Onda firmware install script, and will result in a COMPLETE WIPE and reinstall of Windows - all the files on the Windows partition will be lost. This SHOULD work for anyone whose Android is working but Windows isn't, but I can't guarantee that. I can't even guarantee that this will work (though I am pretty sure it will) - I have not tested it completely. If you can, you should make a backup of anything files on the internal storage, just in case. As always, read the whole procedure before starting.

NOTE: If your Android isn't working, you need to install that first - get the Android file from the Onda Baidu page (look for the one for OBOOK 10 (not SE), with the appropriate V1, V2, V3, V5, or V7 code - you can find your code by checking the serial no. on the back of your device, the 9th and 10th characters), and follow the instructions in the document included in the zip - they are pretty straightforward, but you'll have to use Google Translate, as they're in Chinese. This MUST be done before the Windows procedure, because the Android installer wipes the entire disk.

If you want, you can make the procedure easier for yourself and save all the commands below to a text file, put it in the root folder of the USB before booting, and open it in Notepad by using:

notepad D:\textfile.txt

Or whatever name you give it. That way, you can copy paste them all easily.

Boot into the Windows installer, and when the command window appears, press Ctrl-C. After a few seconds, it will ask you if you want to terminate batch job, type 'y' and press enter. You now have a command prompt to work with.

You have to delete your Windows partitions first. The below partition numbers should be correct, but you should make sure first by running "list partition" and checking if it corresponds with the last 3 partitions, which should be your Windows partitions - their sizes are usually 128 MB, 35 GB, and around 800-1024 MB, and their types are Reserved, Primary, and Recovery (DO NOT delete the Primary partition at the beginning of the disk). DO NOT delete the Unknown partitions - those are Android's.

diskpart
sel disk 0
sel partition 14
delete partition
sel partition 13
delete partition
sel partition 12
delete partition

Your Windows partitions are now completely gone, so you'll have to recreate them first.

Change directory to the images folder.

cd D:\images

Get filesizes of .wim files to create partitions accordingly:

for %I in (Install.wim) do set INSTALL_SIZE=%~zI
set /a INSTALL_SIZE_MB=%INSTALL_SIZE:~0,-6%
for %I in (Winre.wim) do set RE_SIZE=%~zI
set /a RE_SIZE_MB=%RE_SIZE:~0,-6%
if %RE_SIZE_MB% LSS 430 (set /a RE_SIZE_MB=480
) else (
if %RE_SIZE_MB% GEQ 430 (
if %RE_SIZE_MB% LSS 680 (
set /a RE_SIZE_MB=%RE_SIZE_MB%+320
) else (
set /a RE_SIZE_MB=%RE_SIZE_MB%+1024
)
) )

Make sure to preserve all the spaces and brackets in the above code.

Enter diskpart, run the following:

sel disk 0
create partition msr size=128
create partition primary
shrink minimum=%RE_SIZE_MB%
format quick fs=ntfs label="Windows"
assign letter="W"
create partition primary
format quick fs=ntfs label="Recovery"
assign letter="R"
set id="de94bba4-06d1-4d40-a16a-bfd50179d6ac"
gpt attributes=0x8000000000000001

You should now have 14 partitions when you do "list partition".

Exit diskpart.

Now for the actual installation:

md w:\recycler
md R:\recovery\windowsre
DISM /Apply-Image /ImageFile:"D:\images\Install.wim" /ApplyDir:w: /Index:1 /Compact /ScratchDir:w:\recycler
xcopy D:\images\Winre.wim r:\recovery\windowsre /y

Create boot entry:

bcdboot w:\WINDOWS
If that doesn't work, then:
w:\WINDOWS\SYSTEM32\BCDBOOT w:\WINDOWS

Set recovery environment:

w:\windows\system32\reagentc.exe /SetREImage /Path R:\recovery\windowsre /target w:\windows

And that's it! You should have both OSes operational now.