Re: [Tails-dev] TAILS on Windows Tablets?

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Autor: Peter N. Glaskowsky
Data:  
Dla: intrigeri
CC: tails-dev
Temat: Re: [Tails-dev] TAILS on Windows Tablets?
> On Mar 19, 2015, at 9:38 AM, intrigeri <intrigeri@???> wrote:
>
> Hi Nathan,
>
> Nathan of Guardian wrote (19 Mar 2015 15:52:18 GMT) :
>> Has anyone tried booting TAILS on this new class of cheap Windows 8.1
>> tablets?
>
> Peter (Cc'd) has sent us some reports about it on tails-ux@???
> (sic), some of it having also landed on
> https://labs.riseup.net/code/issues/6064#note-8 and further notes.


Basically, some Bay Trail tablets can get to GRUB readily enough, but it’ll take some more work to make them boot Tails.

>> It seems viable and cheap. I haven't picked one up yet, but plan to
>> shortly.
>
> Same here: https://tails.boum.org/blueprint/UEFI/32-bit/#hardware
> (mostly as part of adding support for 32-bit UEFI, but also to start
> getting some feeling of the amount of work needed to make Tails work
> on x86 touch devices -- I'm always asked about such things)
>
> My main fear is that it's still unclear which ones of those devices
> can cold-boot from USB, as opposed to "starting Windows and then using
> the 'boot from USB' feature". I'll warmly welcome any report about
> it :)


My interest is in dedicating one of these tablets to Tails by installing the OS on the internal hard disk. They’re certainly cheap enough (under $70 delivered for the WinBook TW700) to make that a reasonable option for almost anyone.

That would require minor changes to the Tails installer so we can boot once from a USB flash drive or a USB DVD drive, then aim the installer at the internal storage. This makes the cold-boot question a non-issue and frees up a USB port while the system is running.

Most of these tablets have only one USB OTG port, which is also the only charging port, which is inconvenient for Tails running from USB. The user would have to set up a USB hub before booting in order to access a second USB device while running Tails, and simultaneous charging is generally not possible.

Fortunately the TW700 has two USB ports, which is a huge advantage here, but it’s the only one I know of that does.

I took some time today to go through the Bay Trail tablets I own to confirm which of them can cold-boot from USB:

Dell Venue 8 7000, a Bay Trail tablet with Android: Not yet.

The default configuration apparently has no way to boot from USB, but this web page:

http://unlock-bootloader.info/mp3-0/dell-venue-8-7000-6714.html <http://unlock-bootloader.info/mp3-0/dell-venue-8-7000-6714.html>

describes a procedure for unlocking the device’s bootloader, which might eventually make it possible to boot something other than Android. But it would probably take a lot of work.

HP Stream 8: Sort of.

Hold down Vol-, press Power for about a second, and release Vol- when the boot options screen comes up. That screen gives access to a Boot Device Options menu, BIOS Setup, and other functions. There’s even a nice little on-screen keyboard that shows all the keys necessary to use these screens. But…

When you get into the Boot Options Menu, you can select Boot from EFI File and push the soft Enter key… and then, with a Tails boot drive, it goes to a File Explorer screen to allow the user to choose between booting from the Tails volume and the NO VOLUME LABEL volume on the USB thumb drive. But there’s no way to press Enter! The Stream 8 has a capacitive Windows button on the bezel, and that just isn’t active at this point. There isn’t a timeout autoselect for the first (presumably correct) option, either.

Of course this all works fine if you hooked up an OTG-Type A adapter cable, a USB hub, your USB thumb drive, and a keyboard. But who wants to go through all that??

I’m sure this could be fixed in software, but it wouldn’t be worth creating a custom boot method just for one tablet.

Toshiba Encore 2: Yes.

With the machine cold, hold down the Vol+ button, then hold down the Power button, until the boot selection menu appears. Select the desired boot device and press the Windows key.

WinBook TW700: Yes, but…

The only way I’ve found to cold-boot the TW700 from USB is to configure the UEFI BIOS to put “USB HD” above the Windows Boot Manager or the internal eMMC storage. Then the USB device needs to be in the Type A port, not the Micro USB OTG port. Once those changes are made, the tablet will boot from USB without pushing any buttons, and you can still use the OTG port to power the tablet while running from Tails or other live USB OS. So this is a usable solution, and arguably superior to the other tablets for those who expect to use Tails more-or-less exclusively.

I’ve added these notes to https://labs.riseup.net/code/issues/6064 <https://labs.riseup.net/code/issues/6064> as well.

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