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[Guide] Drive and Partition Images: Overview

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[Guide] Drive and Partition Images: Overview

Postby bodge99 » May 24th, 2015, 10:02 am

Hello All.

As part of the process in providing drive and partition images I've written a brief overview. Full details will be in provided in the guide.


Drive and Partition Images: Overview.

I've supplied images for each of the original tablets in the Linx range. Namely the Linx 7, Linx 8 and Linx 10.
I have not seen the 3G versions of these tablets and so cannot comment about any possible differences with these.

The images have been created with a Linux based toolset. A copy of the toolset and a guide to using it will be available on this forum as soon as possible.

The images are basically "bare metal" i.e. binary copies of each tablet drives and individual partitions. Each image is compressed to minimise the file sizes as much as possible.

Most people will probably just need the toolset and the relevant full drive image archive. The "tinkerers" out there can either produce their own partition images with the toolset, or download them from here.

Archive image files:

Full drive Images:

These come as two files, the full drive image and a checksum file. An example for the Linx 10:-

Linx10FullDrive.img.gz (compressed image file)
Linx10FullDrive.img.gz.sha256 (checksum file)

The full drive archive is a gzipped binary image of the full drive. Its size is approximately 5GB and is therefore too large for a device (e.g. a flashdrive) formatted with the fat32 file system. You will require either a NTFS (windows) or a Linux filesystem (EXT3 or 4 recommended) formatted device. All of this is covered in the guide.

The checksum file is a text file. Most users will not need to know the details of this file but for the technically minded folk: The contents are a 256 bit checksum of the relevant file created by the Linux utility 'sha256sum' and is computed as described in FIPS-180-2. Any competent Windows based checksumming tool should be able to handle this file.

Partition Images: These are identical in format to the above full drive images. I have supplied images of each of the four partitions present on the tablet drive. The first partition is the EFI boot partition. The second partition is a small secure reserved partition.
The third partition is the Windows partition. This leaves the fourth, the Windows recovery partition.

In order to use these partition images successfully, the original partition structure must be in place on the tablet drive.
This can be created manually, but it is much easier to just use the relevant full drive image.

Bodge99

EDIT 25/05/15: To save potentially "painful" downloads, feel free to PM me directly. I can then arrange to post images on DVD or flashdrive etc.
Beta versions of the toolset are available now. These are specifically tailored to each tablet model. The finished version will be smaller and will handle all three of the tablet models.
bodge99
 

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Re: Drive and Partition Images: Overview

Postby richbowman » May 27th, 2015, 7:28 am

Brilliant! Thanks for this. Will have a go when the images are available- currently am having to use one of my license keys on my Linx 8 (from another device - which will need it soon) after c*cking up a re-install. Would be great to get it back to the original image.

Thanks again,

Rich
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Re: Drive and Partition Images: Overview

Postby Deleted User 1605 » May 27th, 2015, 10:39 am

Hello All.

Here is an outline of how to use the toolset. This is an early draft, it will change slightly as the toolset is developed.

Beta toolset: Description and Usage Overview.

The toolkit, as I have come to refer to this, is essentially a cut down Linux live system.

This has been modified in two ways, firstly, to remove some of the irrelevant contents to the task in hand (e.g. image processing software and the office suite etc.). Secondly, system modifications have been made to allow specific system support for some aspects of the tablet hardware.

Geeky bit follows. Normal people can jump to the "Usage" section below.

Specifically the latest Linux kernel has been installed. I've added some of my own modifications here, so for any Linux bods out there, please view this kernel as "tainted". Kernel attempts to access RPMB sections have been disabled . This prevents a lot of pointless waiting at boot time (specifically for the Linx 7).

I haven't removed many of the superfluous modules and hardware support etc. as this particular project is part of a larger one. I'll look to providing a fully streamlined version when full tablet hardware support has been finalised. Some required kernel parameters are passed by Grub. Note that the filesystem is contained within a squashfs file, so the overall boot process is slightly different than normal.

The tookit consists of the basic Gnu/Linux tools which are used in a GUI environment. I've chosen XFCE4 as it is fairly lightweight and very easy to configure.

Usage:

After connecting up the hardware (see the guide for full details) and preparing the tablet (charge it). Boot the tablet and enter the firmware (BIOS) settings.
Change the boot order so that your first device is your flashdrive or relevant external device. Save the changes and restart.

On restart, you will now be presented with the Grub bootloader screen. Just press enter to select the default choice here.

The system will now boot. This is a three stage process. Initial file system preparation, initial hardware configuration and finally a "handover" to a graphical user interface.

We are now "ready to rock".

Open a terminal. This is equivalent to a windows command shell (also referred to as a dosbox, command window etc.). The work will be performed from here.

To make things easier to follow, the basic instructions are written in a text file. Open the text editor and browse to the instructions.txt file. Open the file and leave it open for reference.
You can "copy and paste" each line or type it into the terminal window, as you prefer.

Now to "connect" the location of the full drive archive to a known location in the filesystem. Linux does not use the concept of drive letters. Any external device is literally "mapped" into the filesystem.

Second semi-Geeky bit. Normal people jump to "Continued Here" below.
In Unix type operating systems, everything is viewed as either a file or a process. There is a special directory that holds "files" that are essentially interfaces between the operating system and all of the hardware.
This is the "device" directory. It's full directory path is /dev .

Each hardware device (whatever it actually is) is given a specific identification name. e.g. the first "hard drive" (or hard drive like device) is described as "sda". The second hard drive as "sdb" and so on.
Delving into the first hard drive as an example.. The first partition on this drive is known as "sda1", the second as "sda2" and so on.

The tablet drive is a memory chip block device. The full "drive" is seen by the system as "mmcblk0".
The first partition is seen as "mmcblk0p1", the second as "mmcblk0p2" and so on.
So, as an example, the full directory path to the third partition (at system level) of the tablet drive is /dev/mmcblk0p3 .

Continued Here.

The process used here to restore the tablet drive from the compressed archive is a low level one which bypasses the normal file handling procedures. Essentially the archive is uncompressed "on the fly", with the extracted data being directly written to the tablet drive.
This takes approximately 15 minutes or so. This It depends on how fast your devices are, the relative speed of the USB port (slow) and how good your USB hub is.

In order to be able to bypass normal system safeguards, these operations have to be performed with elevated user privileges.

So, type the following into the terminal and press enter. Comments are shown here within braces {comment} and are not to be entered.
Edit: Be aware that Linux is case sensitive, so "readme.txt" is different to "ReadMe.txt". The same applies to any typed commands etc.

sudo su {Press enter. Become the "Super User" aka "Root"}

mount /dev/sdb1 /mnt {Press enter. Connect the archive location drive to a known position within the filesystem. Specific discussion about this will be in the guide.}

cd /mnt {Press enter. Change to this location.}

Now choose the relevant command from the three below. It should be obvious which one is required.

gzip -cd Linx7FullDrive.img.gz > /dev/mmcblk0 {Press enter. This is for the Linx 7.}
gzip -cd Linx8FullDrive.img.gz > /dev/mmcblk0 {Press enter. This is for the Linx 8.}
gzip -cd Linx10FullDrive.img.gz > /dev/mmcblk0 {Press enter. This is for the Linx 10.}

The command prompt will disappear for 15 minutes or so. When the write has completed the prompt will return.

Now shut down Linux. Either type "poweroff" into the terminal and press enter or via the GUI menu option "shutdown".
Disconnect all of the external hardware.

All done... Well done..

Now power up your tablet. If all is well, you will see the initial "enter details" screen.

Bodge99.
Last edited by Deleted User 1605 on May 30th, 2015, 8:37 pm, edited 1 time in total.
Deleted User 1605
 

Re: Drive and Partition Images: Overview

Postby Deleted User 1605 » May 28th, 2015, 3:57 pm

Hello All.

I've been having a little rethink regarding the full drive image files. i.e. how they are going to be downloaded and the most convenient common media format that will be used to store them. I'm trying to view this from the user's point of view.

I'm now of the opinion that it might be a good idea to implement file splitting. I think that a 1 GB file size for the split would seem to be a reasonable compromise. This will apply to both the toolkit and the drive images. You can use something like Winrar to "reassemble" the toolkit iso for use with Rufus.

This would mean that each full drive archive could be stored or used with the toolkit from any device with just about any filesystem. (e.g. Fat32, NTFS or any Linux filesystem.)

It would also be easy to supply a toolkit with the relevant full drive image embedded into the iso.
This would mean that all you would need is a 8Gb flashdrive or a dual layer DVD (for use with an external DVD drive). It should also be possible to use an SD card.

If there is any interest, I'll have a look to see if it is possible to use the microSD slot. It might be possible to use this for booting purposes...
I've had a couple of ideas and I think that there might be a way to enable microSD card booting from the EFI shell. This would require a few little mods to something that I've been playing with.. There should be sufficient room available in the EFI partition for this. Therefore no changes would have to be made anywhere else.

No promises.. we'll see...

Any comments on any of this? Any and all feedback appreciated.

Bodge99
Deleted User 1605
 

Re: Drive and Partition Images: Overview

Postby Deleted User 1605 » May 29th, 2015, 1:28 pm

Hello All,

I've gone with file splitting as per my previous post. This will mean a slight change to the user instructions and toolkit.
I'll take the opportunity to make a few further little changes to the toolkit as well.

The full drive archive will be available as described below. This is an example for the Linx 7.

Full drive archive: 4 x 1Gib files + "whatever's left"

Linx7FullDrive.img.split.gz_aa 1024 MiB
Linx7FullDrive.img.split.gz_ab 1024 MiB
Linx7FullDrive.img.split.gz_ac 1024 MiB
Linx7FullDrive.img.split.gz_ad 1024 MiB
Linx7FullDrive.img.split.gz_ae 541300 KiB

Archive file checksum files:

Linx7FullDrive.img.split.gz_aa.sha256
Linx7FullDrive.img.split.gz_ab.sha256
Linx7FullDrive.img.split.gz_ac.sha256
Linx7FullDrive.img.split.gz_ad.sha256
Linx7FullDrive.img.split.gz_ae.sha256

The idea of this is so that any downloaded file can be checked for consistency. i.e. that it has been downloaded without error.

The equivalent files for each partition follow the same naming convention.

The use of these files will be fully covered in the guide.

The new extraction and "write to the tablet drive" command is:
cat Linx7FullDrive.img.split.gz_* | gunzip -c > /dev/mmcblk0


Bodge99.
Last edited by Deleted User 1605 on May 29th, 2015, 3:35 pm, edited 1 time in total.
Deleted User 1605
 

Re: Drive and Partition Images: Overview

Postby Deleted User 1605 » May 29th, 2015, 2:56 pm

Just for completeness:

The full file list for the Linx 7 partitions. Only the recovery partition needed to be split.
Listing shown in partition order.

1st partition. EFI
Linx7Part1.img.gz
Linx7Part1.img.gz.sha256

2nd partion. Reserved/secure.
Linx7Part2.img.gz
Linx7Part2.img.gz.sha256

3rd partition. Windows.
Linx7Part3.img.gz
Linx7Part3.img.gz.sha256

4th partition. Recovery.
Linx7Part4.img.split.gz_aa
Linx7Part4.img.split.gz_ab
Linx7Part4.img.split.gz_ac
Linx7Part4.img.split.gz_ad
Linx7Part4.img.split.gz_ae
Linx7Part4.img.split.gz_aa.sha256
Linx7Part4.img.split.gz_ab.sha256
Linx7Part4.img.split.gz_ac.sha256
Linx7Part4.img.split.gz_ad.sha256
Linx7Part4.img.split.gz_ae.sha256

Bodge99

Edit: It should also be possible to mount these images as loopback devices to allow individual file extraction...
Deleted User 1605
 

Re: Drive and Partition Images: Overview

Postby Deleted User 1605 » May 30th, 2015, 10:03 pm

Hello All,

Just a little update..

I've spent most of the last couple of days working on the toolkit and preparing the drive and partition images to send to Admin.

Today was "one of those days" where just about everything I touched didn't work out quite as planned. I assume most out there know the feeling..

Anyway, SWMBO is in and out of hospital at the minute, so I'm going to be busy ("AFK", as Sheldon [Big Bang Theory] would say.)

In order to get the archives and a working toolset available more quickly, I've reverted to an earlier version of the toolset for now.

This doesn't have the kernel version or some of the mods that I would like to use. I've still disabled access to the RPMB* sections (RW access fails as these areas are not true partitions on these tablets). This has been done by a global filter setting in the LVM config file.

Just final functional tests to conclude and then I'll send everything off.

Bodge99

*eMMC Replay Protected Memory Block. You really don't want to know...
Deleted User 1605
 

Re: Drive and Partition Images: Overview

Postby Deleted User 1605 » May 31st, 2015, 9:02 pm

Hello All.

I've just discovered a little booboo in the archive extraction and write command. :oops:

I was using:

cat Linx7FullDrive.img.split.gz_* | gunzip -c > /dev/mmcblk0

The first person to spot the mistake (given the filenames used here) gets a cookie. ;)

This shows two things:

If anyone is actually reading this... and the value of testing something in its entirety before issuing it.

Bodge99
Deleted User 1605
 

Re: Drive and Partition Images: Overview

Postby richbowman » May 31st, 2015, 10:00 pm

Following with interest - but no idea what the error is (not used Unix for good few years - and even then we had the luxury of a Sun GUI...)

Cheers (especially for all your efforts!),

Rich

P.s. Hope the boss is doing okay.
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Re: Drive and Partition Images: Overview

Postby Dann » May 31st, 2015, 10:04 pm

Just an update;

We're working with bodge99 to get the Images on a DVD, and then i'll upload them to the site, they'll be in a password protected area which some of you might have already seen.

We will only provide access if you can provide proof you've got a Linx tablet.. this is just to stop Microsoft getting arsey with us!
Dann
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