Editing the read-only parts of an image

[Devilfish]

Enigma images are created in such a way that there is a read-only section of the image and read/write section. The /var folder and /tmp folder is the old folders in an image that you can edit. If, for any reason, you want to edit the read-only folders, i.e. /bin, /etc, /lib, /share, etc. this is what you'll need to do.

First of all, you'll need a linux platform to make your changes. This could be a PC with a linux OS, i.e. Ubuntu, or you could have a program called VMWare which is a virtual machine that allows you to run a different OS from within an existing OS. It's up to you which one you choose and I will not go into setting it up in this thread.

Telnet to the dreambox...
username: root
password: dreambox

Follow these commands...

 mkdir /var/tmp/root

 mount -t squashfs -o ro /dev/mtdblock/5 /var/tmp/root

 cd /var/tmp

 tar -cf root.tar root

FTP the root.tar to your linux desktop and open a terminal.

cd Desktop

 tar -xf root.tar

Leave the terminal window open.

Treat the root folder on the desktop as the box itself but don't add or change anything in /var because that is a different location.

When you have finished go back to the terminal window and...

 ./mksquashfs root mtd5.img -be

Then ftp the mtd5.img back to the box. You will need a copy of mksquashfs on the Desktop to be able to perform this command.

Telnet back to the box and...

 cd /tmp && eraseall /dev/mtd/5 && cp mtd5.img /dev/mtd/5 && reboot

Done.

To check what mtd# ...

more /proc/mtd

...but most squashfs are mtd5.

Njoy!

[mattwills71187]

is there anyway to do this from a Pc running on windows

[beady]

is there anyway to do this from a Pc running on windows

No, but you can install a virtual linux machine, using e.g. vmware, and do it from there. It's fairly easy to set up, and there's plenty of guides on the interweb.

[ronlkh]

can anyone please tell me if this method works? I have tested so many times but not working. I have done and follow devilfish's instruction. I am able to produce mtd5.img but when I flash back to the box, the box dont work at all. Can someone please advise me?

Thanks

[DavC]

will this method work for neutrino on the dbox as well?

[mrdude]

can anyone please tell me if this method works? I have tested so many times but not working. I have done and follow devilfish's instruction. I am able to produce mtd5.img but when I flash back to the box, the box dont work at all. Can someone please advise me?

Thanks

Yes of course it works - This is the exact method I used to make the moddified jade image I posted in here.

[ronlkh]

must I umount the root and delete the root.tar before I flash the new mtd5.img?

Thanks

[ronlkh]

What I am running is vmware + ubuntu 8.04.

First I telnet to the dm500 from ubuntu terminal
then I make directory
root@dm500 ~ #mkdir /var/tmp/root
root@dm500 ~ #mount -t squashfs -o ro /dev/mtdblock/5 /var/tmp/root
root@dm500 ~#cd /var/tmp
root@dm500 /tmp #tar -cf root.tar root
root@dm500 /tmp #
then I open another terminal to ftp to dm500
root@ubuntu8041:/home/user/Desktop# ftp 192.168.0.112
Connected to 192.168.0.112.
220 Welcome to the PLi dreambox FTP server
Name (192.168.0.112:user): root
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> cd /tmp
250 Directory successfully changed.
ftp> get root.tar
ftp>bye
root@ubuntu8041:/home/user/Desktop# tar -xf root.tar
root@ubuntu8041:/home/user/Desktop# ./mksquashfs root mtd5.img
I mksquashfs back the original root and a new mtd5.img is created.
then I ftp back to dm500
root@ubuntu8041:/home/user/Desktop# ftp 192.168.0.112
Connected to 192.168.0.112.
220 Welcome to the PLi dreambox FTP server
Name (192.168.0.112:user): root
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> cd /tmp
250 Directory successfully changed.
ftp> put mtd5.img
ftp>bye
exit back to Desktop and telnet back to the box
i change the directory to /tmp
root@ubuntu8041:/home/user/Desktop# telnet 192.168.0.112
Trying 192.168.0.112...
Connected to 192.168.0.112.
Escape character is '^]'.

PLi dm500 Jade 20080718 (based on 1.09)
welcome on your dreambox! - Kernel 2.6.9 (13:08:41).
dm500 login: root
Password:


BusyBox v1.01 (2008.07.11-10:44+0000) Built-in shell (ash)
Enter 'help' for a list of built-in commands.

root@dm500 ~ # cd /tmp && eraseall /dev/mtd/5 && cp mtd5.img /dev/mtd/5 && reboot

after image flashed dm500 reboot but dm500 is dead

I did not umount the root directory in the /var/tmp nor I have deleted the root.tar

Have I done anything wrong?

[Devilfish]

On a working image, do a 'more /proc/mtd' in telnet and see what it says.

[ronlkh]

Hi Devilfish,
What I got is :-

root@dm500 ~ # more /proc/mtd
dev: size erasesize name
mtd0: 00600000 00020000 "DreamBOX cramfs+squashfs"
mtd1: 001c0000 00020000 "DreamBOX jffs2"
mtd2: 00040000 00020000 "DreamBOX OpenBIOS"
mtd3: 007c0000 00020000 "DreamBOX (w/o bootloader)"
mtd4: 00800000 00020000 "DreamBOX (w/ bootloader)"
mtd5: 004e0000 00020000 "DreamBOX SquashedFS"
mtd6: 00120000 00020000 "DreamBOX Cramfs"

thanks

[Devilfish]

That looks right, was just checking that the squashfs part was indeed mtd5. Not sure what else to suggest. Maybe try a totally different image.

[unai_goiko]

Hello there! I've just found this forum and have to say that i'm impress with it

Continuing with the thread, I'm having the same problem as ronlkh here. I followed the steps explained by Devilfish except from the part of using a mksquashfs binnary copied on the Desktop. I used the mksquashfs binnary from ubuntu instead. Then, after rebooting, the dreambox does not respond and i get a black screen...

I've read that squashfs-lzm is used for building most of the dreambox images, shouldn't will be using that program? Thanks in advance!

[ajeeb]

@Devilfish hi
maybe this cause the problem? to get it works?

root@dreambox:/tmp> tar -cf root.tar root       
tar: Names longer than 100 chars not supported
tar: Names longer than 100 chars not supported. 
tar: Names longer than 100 chars not supported.

br

[mat989]

Devil: I have some questions.

1. What is /dev/mtdblock/5? There is also /dev/mtdblock/6 in the rcS file.

2. If I am going to replace the "bild" file, does that mean i need to apply your method, but instead of mounting /dev/mtdblock/5 in read-only-mode, i shall mount /dev/mtdblock/6 ?

3. In summary what you did is this:

• Dreambox: Backup the section you want to edit
• Dreambox: Transfer the backup file to your linux box
• Linux Box: Extract the backup file and edit the files
• Linux Box: Generate the squashfs file and transfer the file to the dreambox
• Linux Box: Replace the old section with the updated file and reboot the dreambox "How is this going to work? You are still in read-only mode?!! I shall try it first!"

thnx...

[Devilfish]

If you type more /proc/mtd it will show you the different memory locations on the dreambox.

mtd5 is the SquashFS section that we want to edit. This is all the folders that you see when you ftp to the box, except /var and /tmp.

So we extract mtd5 from the box, transfer it to our linux PC, edit it as you like and then recompile it back into an mtd5.img. Transfer the mtd5.img back to the box and flash it again. You are not flashing the complete image, only the mtd5 memory location. So now the complete image on the dreambox should have your edits.

In the DK images, the bild file is in /bin so you can easily edit it using this method.

@ajeeb, I completed that command without any problems on my dreambox. (see pic)