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Hardware Hacking Android Debian Handhelds Portables

How I Freed My Android Tablet: A Journey in Reverse Engineering (www.thanassis.space) 79

Slashdot reader ttsiod is an embedded software engineer at the European Space Agency, and shares this story about his quest to "dominate" his new tablet: Just like it's predecessor, I wanted to run a Debian chroot inside it -- that would allow me to apt-get install and run things like Privoxy, SSH SOCKS/VPN tunnels, Flask mini-servers, etc; and in general allow me to stay in control. But there was no open-source way to do this... and I could never trust "one-click roots" that communicate with servers in China... It took me weeks to reverse engineer my tablet -- and finally succeed in becoming root. The journey was quite interesting, and included both hardware and software tinkering. I learned a lot while doing it -- and wanted to share the experience with my fellow Slashdotters...
He writes that "I trust Debian. Far more than I trust the Android ecosystem," and describes everything from how he probed the boot process and created his own boot image to hunting for a way "to tell SELinux to get off my lawn".
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How I Freed My Android Tablet: A Journey in Reverse Engineering

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  • by Anonymous Coward on Sunday November 06, 2016 @03:46PM (#53224437)

    At one point in time every kind of personal computer you could buy would be yours.

    Then people started buying locked down devices, which became a bigger and bigger part of the market. Because why not? People buy them, and it's better for the selling company to maintain control of the device so they can exfiltrate your data, lock you into their software store to reap a cut off the top, or disable the device remotely.

    But, generally, you could still get past against-the-owner security in various ways. But companies are learning from the holes, and each generation is more difficult to bypass. Even whitebox PCs are moving in this direction.

    The ownership-era for general purpose computing devices is drawing to a close. Step back to 1970's someone playing with their Apple II or C= Pet and try to explain to them that someday, their computer will take orders from someone else in preference to theirs. They might not even understand how such a thing would be possible, but a million tiny steps have led us to our cages. The next million tiny steps will throw away the key. At each step, people get to argue, "THAT step didn't cause the problem. Why are you complaining so much??"

    Thus ends the potential freedom brought about by the computing revolution.

    • by spire3661 ( 1038968 ) on Sunday November 06, 2016 @03:50PM (#53224449) Journal
      You do realize Stallman has been saying this stuff since the 70s right? Its been a known problem for a VERY long time and we fought the good fight for as long as we could, but pocket computers killed it.
      • by Anonymous Coward

        we fought the good fight for as long as we could, but rampant technical illiteracy killed it.

        FTFY.

        • by Anonymous Coward

          Don't confuse illiteracy with complacency. Thereeven are plenty of capable people out there.
          NOBODY CARES.
          Why should they?

        • Always-connected Internet made securing your machine impossible. This was the innovation that took away permanent control over your machine. After all, you "need" to install security patches so *other* programs or people on the Internet can't take over your machine, right? This means you can never "fix" your machine to a set configuration. You trust someone else to update your machine, and these updates keep control over you.

      • by Kjella ( 173770 ) on Sunday November 06, 2016 @04:40PM (#53224651) Homepage

        You do realize Stallman has been saying this stuff since the 70s right? Its been a known problem for a VERY long time and we fought the good fight for as long as we could, but pocket computers killed it.

        Well I think it swings both ways, it's more and more obvious that you don't really control any closed source operating system, you pretty much must have security patches and everything else comes along for the ride and increasingly it can't be configured or disabled. That's the way of iOS, Android, Win10, they're trying to push that model on Win7/8, I'm not sure about OS X but they're probably not far behind. If you want control, you want Linux (or some other open source OS). That said, most people don't felt they were in control at all. By making Apple/Google/Microsoft the gatekeeper, they trust just one source instead of any random exe from the Internet. Same way most people want the CA system instead of messing with peer-to-peer trust. Because when they don't understand - and they won't understand, no matter how much you try to teach them - they end up trusting something or someone.

        That said, what I'm mostly disappointed with is how the world has ended up revolving around a few, huge centralized services. Newsgroups, IRC, Email, blogs and really any kind of service that runs on a network or you could run from your own server is toiling in obscurity, you need to be on Facebook and Twitter and YouTube playing by their rules and if they want to wield the ban hammer there's very little you can do. Personally I'm far more concerned about how we've lost control of the human interaction rather than control over the local machine. And for the most part we don't own things in the digital world anymore we license or stream them, it's all permissions that can be revoked or services that can be shut down. That said, it works surprisingly well until one day it doesn't.

        • by ShakaUVM ( 157947 ) on Monday November 07, 2016 @02:40AM (#53227343) Homepage Journal

          >Well I think it swings both ways, it's more and more obvious that you don't really control any closed source operating system, you pretty much must have security patches and everything else comes along for the ride and increasingly it can't be configured or disabled. That's the way of iOS, Android, Win10, they're trying to push that model on Win7/8, I'm not sure about OS X but they're probably not far behind. If you want control, you want Linux (or some other open source OS). That said, most people don't felt they were in control at all. By making Apple/Google/Microsoft the gatekeeper, they trust just one source instead of any random exe from the Internet. Same way most people want the CA system instead of messing with peer-to-peer trust. Because when they don't understand - and they won't understand, no matter how much you try to teach them - they end up trusting something or someone.

          True. But there's no connection between getting signed patches from Apple/Microsoft/Google and it being FOSS. You can have both. The only reason to lock down a platform so that users can't mess with it *if they want to* is control and money. Taking control away from users and putting it in the hands of A/M/G instead. On cell phones this was justified by the subsidies that cell phone carriers would pay - a carrier wouldn't want someone to buy a subsidized cell phone from them and then switch carriers (notwithstanding that this could just be enforced by ETFs and the like), so cell phones were locked down to remove root access to them. And because cell phones were, tablets have followed along, since tablets are just cell phones with larger screens.

          Google does the minimum to be compliant to the GPL, and Apple and Microsoft barely even pretend. Windows 10 is a disaster for many reasons, but the biggest one to me is that it has finally removed the notion that the owner of a computer is, you know, the owner. Who can modify it to fit his needs as he wishes. Now you're just a user, and even with administrative privileges there are things you will not be allowed to do inside the OS. It's the biggest piece of shit move from the FOSS perspective that the world has ever seen.

          The saddest thing that can ever be said is that Stallman was right again.

      • by rtb61 ( 674572 )

        Cough, cough, they only win, when we stop fighting. Really how much effort does it take to fight. Attack it on forums, every now and again, complain to the government every now and again, join in with consumer rights organisations, join in with personal rights organisation, refuse to buy products that do not serve you, well, do that always, seriously should you allow control over your own life to be treated as an inconvenience.

        New actions, fuck up all their surveys, corporations treat me well and I will t

    • by nnull ( 1148259 ) on Sunday November 06, 2016 @05:09PM (#53224835)
      What I find amazing is to what extent these manufacturers go to stop people from doing anything useful with these locked down devices. Seems to much time and effort is being put into obfuscation (Using even opensource software to do it) than actually making a useful product. My question is, why? Just seems silly and creates a lot more waste. There's so many of these devices out there right now, that doing this is completely pointless and doesn't even guarantee the customer is going to buy your product again.
      • by MrKaos ( 858439 )

        My question is, why?

        Sales. Anything that allows users to re-purpose devices is a sale lost. PC's were re-purposed often, so they learned how to fix that mistake.

        Even better for them is they avoided costs by using the open source operating system designed to make it open, to close it instead.

    • by guacamole ( 24270 ) on Sunday November 06, 2016 @06:54PM (#53225423)

      Because 99% of consumers do not even know the difference between locked and unlocked device, and most won't even care, sadly.

    • +1000
    • To be 100% accurate, Nexus devices are yours. You can load a ROM that is pre-rooted and then do everything you want. Bootloader locks are a side-effect of the way Americans buy their smartphones, which is basically that they do not own them for the first one or two years but instead borrow them from the carrier 'till they pay them off during the course of the contract. So, the device is not yours to tinker with. Even before Android, there were all kinds of locks in the software for the carrier's behest.
      • To be 100% accurate, Nexus devices are yours.

        It's a shame they've taken that away with their new Pixel line.

  • Very very impressive. But of course, now we know you can do this, landing some more expensive stuff than a tablet on Mars without breaking it should be on your To Do list...

    Bert
    (You probably saw that one coming, didn't you?)

  • by Virtucon ( 127420 ) on Sunday November 06, 2016 @04:18PM (#53224527)

    Great read.

  • by Anonymous Coward

    Good job achieving what millions did already. Just buy a noname tablet from China, they don't care if you root it, and there are probably dozens of ROMs to choose from.

  • Impressive (Score:5, Insightful)

    by JustAnotherOldGuy ( 4145623 ) on Sunday November 06, 2016 @04:52PM (#53224743)

    Gotta give this guy credit for doing some serious detective and reverse-engineering work. Good job.

  • This is pretty awesome, and something I wish I could do.... just far too complex and involved for me.

    I just kinda gave up, have plans to use an offline Android tablet, but for online stuff falling back to laptops with something like Qubes, Tails and whatnot.

    I know there are some alternatives out there, but they are usually either very expensive or hard to get, and you end up in the same situation where you have to trust the guys who did it (stuff like Aquaris M10 Ubuntu tablet, Copperhead OS, BlackPhone 2).

    • by ttsiod ( 881575 )
      > In any case, kudos to ttsiodras(?)

      Thanks - that is indeed my handle nowadays. Though when I opened my Slashdot account back in my Uni days I went with 'ttsiod' - our mainframe (I believe it was called "Cyber"?) could only accommodate a maximum of 6 or 7 letter login names :-)

      • by MrKaos ( 858439 )

        Thank you ttsoid! Suddenly all my old knowledge about serial became relevant again. Seeing you blog about serial ports, stty, was really nostalgic, I didn't realize it would be useful in the android domain. I'd say the tablet has a lot more computing power than those old machines had.

        Coincidentally this article came when I am upgrading phone and tablet, which is also an asus, so I am set up to try some of the hacks you have described. I'm keen to see if the serial ports are on the headphone ports of the p

  • by Anonymous Coward

    Only LUDDITES would ever think of installing LUDDITE Debian on an app apping device!

    Apps!

  • by Qbertino ( 265505 ) <moiraNO@SPAMmodparlor.com> on Sunday November 06, 2016 @06:28PM (#53225279)

    The tenacity is noteworthy. This guy did a very good job at getting to the bottom of things and enabling total control over his tablet.
    Well done!

  • I have an Android tablet for which root and TWRP are available as is without any trouble (thanks Samsung). The thing I am wondering about is why I'd need to install Debian chroot on it? Aren't Linux apps mostly optimized for computers with keyboards and all. What is its killer app?

    • I have an Android tablet for which root and TWRP are available as is without any trouble (thanks Samsung). The thing I am wondering about is why I'd need to install Debian chroot on it? Aren't Linux apps mostly optimized for computers with keyboards and all. What is its killer app?

      You mean there are no libre-linux ways to chroot that tablet?

    • by dbIII ( 701233 )

      The thing I am wondering about is why I'd need to install Debian chroot on it?

      For when you want something that doesn't work with the version of Android that came with the device. The Debian portion can be updated but for a lot of Android devices you are stuck with the version that came with it.
      The killer app will be something coming out in a year or two that you can't run without getting a new tablet or running different software on the one you've got. It could even be something like a new ereader file fo

      • The ereader format wouldn't be much of a problem. Android allows you to install alternative browsers and those usually support fairly old OS versions. For example, Firefox for Android supports everything down to 4.0, which is five years old now and probably will remain the baseline for what everyone must support for a few more years as some cheap low-end devices are still released with it AFAIK.
      • That's an argument with many flaws.

        First of all, the Debian Linux applications for the most part are not meant to be convenient replacements for true touch-oriented Android apps. So this is basically about replacing a native touch-GUI optimized by outdated Android app with a relatively clunky Linux equivalent.

        Second, a whole lot of Android devices can get updates by the means of third party ROMs. First of all, the big ROM projects like Cyanogenmod or OmniROM, etc, can cover quite a bit of hardware. Another

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