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 Message Boards » » Help with Embedded Linux Page [1]  
LoneSnark
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I have an HDTV Receiver (Hisense DB-2010) which just so happens to be running an embedded copy of Linux. The Unit works perfectly, but I want to play around with it; regretfully, I am not that adept at Linux. I have an RS232 (Serial) terminal connection to the box, and after bootup I get a prompt for a password.

Now, I found a quote on a message board which is as follows:
Quote :
"[Post 574]
Author : Niacin
Date : 03-28-07 09:50 PM

Codeman and I managed to decrypt the update image. The serial password is "xyzzy" but its actually useless unless there is a file /opt/mediaworks/etc/allowshell on the flash. We are still working on an OTA mod."

http://www.avsforum.com/avs-vb/showthread.php?p=10155405&&#post10155405
The box has a USB Port on the back and I have a USB key plugged into it, on which I created this directory and file using slax, but I didn't know what to put in the file, so I left it blank; suffice to say I still cannot log in using the password Niacin provided. I have posted a reply to the message board asking for additional information, but no reply.

Anyone else have ideas or alternative interpretations of this post?
http://www.linux-hacker.net/usdtv/

5/24/2007 10:44:25 AM

quagmire02
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i never thought of a tv running linux before...seriously, never even entered my mind

i'm interested, though...i'm all about purchasing hardware whose software i can tweak

5/24/2007 1:12:47 PM

joe17669
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I think all series of Tivos have a version of Linux running on them

5/24/2007 1:48:30 PM

moron
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The file has to be on the devices internal flash rom. It seems you have the file on a USB flash drive.

5/24/2007 2:22:05 PM

LoneSnark
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Ok, but I cannot get it anything onto the internal flash rom without being able to log in. Catch-22. I believe Niacin would have had the same limitation.

5/24/2007 2:24:33 PM

moron
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Yes, that's what he meant by:
Quote :
"but its actually useless unless there is a file /opt/mediaworks/etc/allowshell on the flash. We are still working on an OTA mod."


They would have to find someway to create a modified flash update that has the file.

5/24/2007 2:26:30 PM

moron
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Actually, what I said was wrong. I'm assuming you're Beachhouse, but someone said this in reply to you:
Quote :
"I tried the same thing. That flashware (unless there is new out there) is for non-subscription boxes. Since you always go to channel 99-1, you have a subscription box.

You need a new key or to wait until the software gets posted.

To verify the stick is bootable, use cfdisk /dev/sda. It will tell you if it is bootable by saying "Bootable" next to the partition in the table on the screen. If it is not, use the right arrow to go to Bootable option and hit enter. Then Write the partition. You can also use fdisk and hit 'a'. But there is no menu on fdisk."


The 2 issues you may be having are that your box doesn't support the booting of that USB image, or that your USB image might not be set to bootable.

5/24/2007 2:35:15 PM

LoneSnark
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Well, this is the same USB key I used to re-flash the box to the latest firmware version. So it had no trouble booting from it back then.

But you do bring up a good point. The post I am using to Justify my efforts, that of Niacin, was posted while he was attempting to write a firmware update which was released by the company about a month later. So, it is possible that the password he lists was for the old firmware.

I read that what I can do is revert back to the original firmware. After doing that I should be able to re-flash to the latest, but this time I would modify the script to change the password and otherwise enable remote login.

But I don't think this would work, as it would not modify the files on the internal flash, as I suspect when updating it boots off the USB key, which means any change to system settings performed by this script would have no effect upon the files used to boot from the internal flash...
http://nekkid.homeip.net/data/start

5/24/2007 3:22:27 PM

moron
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Quote :
"
But I don't think this would work, as it would not modify the files on the internal flash, as I suspect when updating it boots off the USB key, which means any change to system settings performed by this script would have no effect upon the files used to boot from the internal flash...
http://nekkid.homeip.net/data/start"


That's right.

If you look at that script, it has a "nandwrite" command that it uses to flash the ROM. You would have to create a binary file to flash to the ROM that has the right file system on it with the allowshell command.

[Edited on May 24, 2007 at 3:44 PM. Reason : nandwrite -j /dev/mtd$FSPART rootfs.jffs2]

5/24/2007 3:39:28 PM

moron
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I have never done anything like this before, but just reading this thread and this http://uuu.enseirb.fr/~kadionik/embedded/uclinux/mtd/howto_mtd.html
It doesn't seem like it would be too hard to add that file. If you know that the STB mounts the USB drive, you could write a script that dumbs the root FS from the flash to the USB, mount the filesystem, make the changes you need, then run the scrip to re-flash the filesystem. If the STB doesn't mount the USB drive, it's a little harder, you'd have to dump the filesystem from another flash.

[Edited on May 24, 2007 at 4:33 PM. Reason : ]

5/24/2007 4:33:13 PM

LoneSnark
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It looks like the only way I can make this change is to change the contents of the rootfs.jffs2, but I can't figure out how to do it.

That said, even if I did I would be too frightened of screwing with the firmware upgrading process, since I fear a bad firmware would render the unit beyond recovery. As such, I am going to wait until those that know better come out with a fool-proof mechanism.

Thanks for your help, moron.

5/24/2007 7:49:01 PM

moron
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If you had an original copy of root.jffs2 it wouldn't be too hard. You'd just also need a version of mkfs.jffs2 which is freely available.

But, it also looks like there's 2 copies of the boot software, so if you only borked one, you'd at least have the other to fall back one

5/24/2007 10:26:34 PM

LoneSnark
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I have both versions, but I don't see how that helps, since presumably both include the latest software (only the hardware is slightly different) and therefore suffers the same password problem.

5/25/2007 12:21:17 AM

moron
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Well, if you have the original root.jffs2 file, mount it with these commands, from the link above:

> erase /dev/mtd1

> cp jffs2.img /dev/mtd1

> mount -t jffs2 /dev/mtdblock1 /mnt

You might have to add some jffs2 software to your nix box to do this (the jffs2 stuff isn't standard AFAIK).
Add the file you need. Turn it back in to an jffs2 img with this command:

> mkfs.jffs2 -d jffs2 -o jffs2.img

where the "jffs2" after the "-d" is the location of the mounted directory that's going to be the new directory for the flash ROM.

Then replace your new image file with the file system image on the update stuff, and that should put the file there, if i'm understanding things correctly. There may be clearer instructions on google on working with jffs2 but that's the first link I really looked at.



[Edited on May 25, 2007 at 12:30 AM. Reason : clarify]

Also, this assumes that your box is correctly picking up and booting from the USB drive.

[Edited on May 25, 2007 at 12:32 AM. Reason : ]

5/25/2007 12:28:52 AM

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