Bootloader used for x86 tablet

[Ye Roger]

There are many Intel tablet on market now. Do you have any idea what bootloader is used ? Do they use the same bootloader or different ? As what I know, Android-x86 is using Grub. Chromebook use coreboot. How's about tablet such as ASUS fonepad, DELL Venue or HP?

[Povilas Staniulis]

On 2015.05.08 13:14, Ye Roger wrote:

There are many Intel tablet on market now. Do you have any idea what bootloader is used ? Do they use the same bootloader or different ? As what I know, Android-x86 is using Grub. Chromebook use coreboot. How's about tablet such as ASUS fonepad, DELL Venue or HP?

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I think most use Intel's proprietary IAFW bootloader.

[Antony Stone]

I can't answer the last part of your question (although I hope that others
here can), however I thought it worth pointing out that there are several
stages to booting a computer, and you've confused two of them n your
description above.

A "standard" PC contains a BIOS (which is usually programmed into a flash
memory device on the motherboard these days), and this gets the machine going
to the point where it can find a hard disk (or USB device, network interface
for PXE, etc) and then pass control over to a boot loader on that device.

Grub is an example of the boot loader you might find on a hard disk or a USB
device (and even Grub has at least two stages to it, as can be seen from its
status messages as it starts up, or the error messages it can produce when
something goes wrong).

Coreboot (which used to be called LinuxBIOS) is a replacement for the on-board
BIOS code, and in many cases with current hardware can be programmed into the
motherboard's flash chip as a replacement for the BIOS code which the
motherboard manufacturer supplied.

However, coreboot still passes control over to a standard boot loader once
it's initialised the hardware and found the appropriate boot devices, and
again Grub (or some equivalent) then takes over, and gets the O/S kernel into
memory ready to run "the real system".

Since Grub is stored on the mass storage device (hard disk or USB, usually,
although there are also equivalent things like syslinux for CD-ROMs), this is
a trivial thing to replace in a machine, once you know what parameters it
needs, and what sort of kernel it needs to boot, in order to get the machine
going.

What's more interesting is to replace (or even understand) the BIOS on a given
machine, since this is the bit that starts from the moment you press the power
button, and is responsible for initialising and finding the mass storage device
with the main boot loader (such as Grub) stored in its boot sector.

So, there are definitely two parts to your question:

- what do various Intel-based tablets use as a BIOS or equivalent?

- which boot loader do they then use to get the O/S loaded from mass storage?

I hope some others here can fill in the answers to those two question for some
specific devices :)


Regards,


Antony.

--
I conclude that there are two ways of constructing a software design: One way
is to make it so simple that there are _obviously_ no deficiencies, and the
other way is to make it so complicated that there are no _obvious_
deficiencies.

- C A R Hoare

Please reply to the list;
please *don't* CC me.

[Povilas Staniulis]

Well, most ARM tablet bootloaders load the Linux kernel directly. I
guess the same is true for x86 tablets.

[Chih-Wei Huang]

2015-05-08 23:17 GMT+08:00 Antony Stone <Antony...@android.open.source.it>:
> On Friday 08 May 2015 at 12:14:41 (EU time), Ye Roger wrote:
>
> So, there are definitely two parts to your question:
>
> - what do various Intel-based tablets use as a BIOS or equivalent?
>
> - which boot loader do they then use to get the O/S loaded from mass storage?
>
> I hope some others here can fill in the answers to those two question for some
> specific devices :)

As I know so far only Baytrail based tablets shipping
with Android Lollipop use UEFI BIOS and efilinux as
the bootloader. (e.g., ASUS TF103CE / ME176CE)
All the others use proprietary IAFW.

But even for the UEFI based tablets,
it doesn't mean you have a chance to change
or replace the bootloader to boot a customized OS.
The bootloader needs to be signed.
So far there is no official method to
unlock the bootloader.

--
Chih-Wei
Android-x86 project
http://www.android-x86.org

[Ye Roger]

Chih-Wei, thanks! That's the information that I need.