How to Install Windows 10 on an Android or Windows 8/8.1 Tablet

I was experimenting with trying to put Windows 10 Technical Preview on a Windows 8 tablet and decided I would share the information I have learned on the process. But don't get too excited yet, there are many requirements and even then there is still a chance it won't work. Others may have no problem and experience the delight of Windows 10!

Prep, Windows 8 & Android

WARNING: I am not responsible for any damage or issues caused by using the following information.

Windows 10
Windows 10 is still being developed and tested. The newest build has just come out and it will soon be available as an ISO. Microsoft has also stated they are going to start making monthly updates, and that even pirates of Windows 7 will get a free upgrade!

Unlike Windows 8/8.1 on tablets, the Windows 10 OS is meant to be the same for a tablet or a PC. Phones seem to be getting a different version, but who knows how it will end up when finally released.

General Preparation
The first thing you will need to have is a tablet. I would recommend a tablet with at least 32GB built-in, but you might be able to get away with 16GB. Just as important is that the tablet will need to have an Intel CPU. I don't think there are any Intel CPU's in tablets that aren't capable of installing Windows 10.

In addition, ensure that you have a full-sized USB port, or a micro-USB port that supports OTG. In the case of the latter, ensure you have an OTG cable, or an OTG-capable USB flash drive. Speaking of which, you will need a USB flash drive; a drive of 8GB or higher is recommended.

Android users will probably require a keyboard, so be sure to have a keyboard that will work with an OTG cable, or that fits a micro-USB port. If you only have a micro-USB port, and the use of a keyboard is required, you will need an OTG cable splitter that can power items such as a USB flash drive. In this instance, it would be smarter to use a keyboard that is meant for a tablet so extra power is not required from the tablet. Some people may be fortunate enough to have both USB port types, which could make this process much easier.

You will then need to download a copy of Windows 10 for 32-bit. You are supposed to signup for the Windows Insider Program, but there are other ways... Once you have an ISO of Windows 10, use a program like Rufus to make a bootable USB of the Windows 10 ISO image. I believe you will want the GPT option. Choose for a BIOS or UEFI depending on what you have.

Restrictions
The main restriction is to not have a compressed OS. The trouble here is that there are really no documents or articles that will specify if you have a compressed OS or not.

I have read about many popular Windows 8 tablets having this problem, not all of them, but many. The only way I found this out was attempting to install Windows 10 via booting into the USB flash drive. I was not able to do it, so I tried to update through Windows and that's when I received a message stating that I had a compressed OS and could not continue.

I have not read about any Android devices coming across a compressed OS. On the flip side, it is usually argued that most Android devices are incapable of booting from a USB. This is more of a bootloader issue than anything, but if you have an Intel CPU, there is a chance you can still install Windows 10. 

Routes
There are two ways to go about this: Upgrade from within Windows or boot from the USB flash drive and install. Obviously if you have an Android tablet, you will be limited to the latter.

Installing from Windows
This should be fairly easy. As long as your tablet recognized the USB, you should be able to open it up in My Computer and find a setup file to double-click on. You will then either go through the process of installing, or get a compressed OS message.

If you try the next method and cannot complete it despite having met all the requirements, chances are you have a compressed OS. Performing this upgrade from Windows should confirm that.

Installing on a Windows Tablet
This is a bit more detailed, but still a valid method. Ensure you have your USB ready and plugged in beforehand:

1. Go to "PC Settings".
2. Select "Update and recovery".
3. Click "Recovery"
4. Go to "Advanced startup".
5. Choose "Restart now" for booting from a USB device.

If this does not work, see if you can boot directly into the UEFI, which can be accomplished from the PC Settings menu as well. You should then be able to determine which device has boot priority. However, I found that this did not work for my tablet.

If you boot into an installation screen, follow the steps and install Windows 10!

Installing from an Android Tablet
This is a bit tougher than a Windows tablet as you have no option in the OS to boot directly from a USB device.

Because of this, you will likely need to connect a keyboard while your USB is plugged in. It will then be a matter of if you can find a key (likely an F-key) that will allow you to get a priority boot menu to appear. If it does, then you can select to boot from a USB device and press enter. You should then boot into the Windows 10 installation screen and just need to follow any instructions to proceed.

There may be a way to access the boot priority menu without a keyboard, but I have not comes across any articles or posts detailing how if so.

Have Fun!
During installation you should be able to use touch to make choices, so a keyboard should only be necessary in the beginning, if at all. And for those who run into problems, ensure you have met all requirements first and are not limited by any restrictions. Not everyone is going to be able to do this (I would say most), and many tablets will be eliminated by just the first couple sections I wrote.

If I could take a guess, I would have to say Windows 8 tablet owners are more likely to be able to install Windows 10 as long as they don't have a compressed OS.