Bricked Intel Tablet Lives Again

We’ve probably all taken a look at the rash of cheap Intel-Atom-based tablet computers and wondered whether therein lies an inexpensive route to a portable PC. Such limited hardware laden down with a full-fat Windows installation fails to shine, but maybe if we could get a higher-performance OS on there it could be a useful piece of kit.

[donothingloop] has an Intel tablet, a TrekStore Wintron 7, bought for the princely sum of $60. Windows 10 didn’t excite him, so he decided to put Ubuntu on it, or more specifically to put Ubuntu on an SD card to try it on the Wintron before overwriting the Windows installation. His problem with that was a bug in the Baytrail Atom chipset which limits the speed of SD card access and made Ubuntu very slow, and in trying to fix the speed issue he managed to disable a setting in the BIOS which had the effect of bricking the machine. A show-stopper when the BIOS is in a tiny SPI Flash chip and can’t be wiped or restored.

What followed was an epic of desoldering the BIOS chip and reflashing it, though that description makes the process sound deceptively easy. The specification says it is a 1.8V device, so after attempts to flash it using an ESP8266 and then a home-made level-shifter failed, he was stumped. With nothing but a cheap tablet to lose, he tried the chip in a 3.3V programmer, and to his amazement despite the significant overvoltage, it survived. Resoldering the chip to the motherboard presented him with a working tablet that would live to fight another day.

We’d have said that this work might reside in the “Don’t try this at home” category, but since Hackaday readers are exactly the kind of people who do try this kind of thing at home it’s interesting and reassuring to see that it can be done, and to see how someone else did it. A tablet that can be bricked through a mere BIOS setting though is something a manufacturer should be ashamed of.

We like unbricking stories here at Hackaday, something about winning against the odds appeals to us. In the past we’ve covered Blu-ray drives crippled by dodgy DRM and routers rescued with a Raspberry Pi, but the crown has to be taken by the phone rescued with a resistor made using paperclips and pencil lead.

47 thoughts on “Bricked Intel Tablet Lives Again

  1. I’ve encountered the same problem a week ago – here’s a short worklog: https://hackaday.io/project/9729/log/37685 Also, included are instructions for doing SPI programming on a Raspberry Pi =)

    These chips could be re-marked or something. I didn’t see 3.3V anywhere in datasheet, however, it wouldn’t read back correctly at 1.8V and would only behave correctly at 3.3V. Didn’t measure the voltage at which the flash operations in the tablet, though =(

  2. Seems like his webpage couldn’t handle the burden of being referenced ;) Anyway, very interesting story. It could be that the manufacturer specifies the chips according to how do they fare in tests – those able to cope with 1.8V will be marked as such, and the others automatically fall into 2.7-3.6V category. Who knows?
    I like those DataFlash chips, having developed a little device using a 4MB DataFlash as file storage accessible through TFTP. Decent storage size and NOR-flash reliability combined.

    1. i was wondering the same thing, until i read the linked blog post ;-)

      Quote: There is an “Image Update Image” avaliable on the support website of the tablet, which is a 4.8 GB big ZIP file named V1.1.4_WI71C.JGBMRBA05.zip. This file contains the file images/BIOS/TREK.G.WI71C.JGBMRBA05.ROM, which is in fact a complete image of the BIOS flash.

    1. I know that, but full flash should be always full flash, which I tried, because the programming batch file, that came with the original tool was no-go too.
      I played around with it, when I got it working and the official tool never flashed the same bios image correctly. I flashed 1st time with original tool, dumped and rescued via flashrom and raspberry, 2nd flash with original tool, dumped and rescued with flashrom and raspberry. Always the same commandline on the original tool.
      When I compared both the dumps, they were not the same. Not like one or two bytes, but different size chucks of bytes.

    1. Oh and out of curiosity: What setting bricked the thing exactly? And doesn’t it have a more simple BIOS reset functionality? Some pins you need to short to reset it?
      And talking of which, I think any BIOS can be messed with in such a way that the device stops working, but that’s why all motherboards always have a BIOS reset, so I just think there is some undocumented way to do a simple reset.
      I mean I can’t imagine a standard plug-in motherboard like it is used on cheap devices completely missing such a basic functionality.

      1. Addendum: NM site works now, and he did look for the BIOS reset and for some possible reset-pads
        To quote:

        So what I learned from this was that BIOS updates work by backing up the NVRAM section of the flash to RAM, completely erasing and programming the flash and afterwards restoring the NVRAM to the chip, which is quiet neat in case of damaged settings. But I really hope that in future Tablet manufacturers will include some sort of reset points for the BIOS settings, especially if there are severe bugs which lead to a hard-brick by simply changing a setting

  3. I’ve seen reports that just changing the setting which controls if the machine is off/on/last state after the power supply is reconnected is enough to brick some boxes similar to the pipo x7. Mind you I don’t remember for what box exactly I’ve seen this, just giving the pipo as an example that is easy to google.

  4. What was wrong with Win 10? lmao you put linux on it for what? To browse the web like you do with Windows? That is all anyone with tablets do. They are info consumers not producers.
    Aside from that an informative guide of BIOS repair.

    1. I know where everything is in Linux, I don’t feel like a passenger.

      I have a Surface 2 tablet, won it in a contest. It’s great for consuming,

      But last year an update went bad, Microsoft’s fault. So I ended up losing the files I’d downloaded to it.
      If it had been running Linux, this wouldn’t have happened, but if it did I’d be able to salvage things, I know Linux.

      The Surface 2 is the first “main” computer I’ve ever used that ran a Microsoft operating system. That goes back to 1979.

      So why would I want to run Windows?

      Michael

    2. The only Linux distro that worked for me out of the box when I needed was Raspbian on RPi3. Windows works always on normal computers. Linuxes are more server-oriented and they are great there, but on normal desktop/laptop/tablet-pc they either don’t work or are somewhat fragile to configuration of simple things. Yesterday I read complaint of someone, who bricked his Ubuntu by changing wallpaper…

    3. Perhaps he doesn’t want to spend time on sending every bit of private information including his router/wifi’s passwords to MS (and ‘friends’)?
      Perhaps not having to run 20 spy programs and pointless crap on a device with 1GB of RAM total will be a bit beneficial, even when browsing?

  5. Can someone hack the old Baytrail Motherboards found on these tablets to boot without a battery??

    I have three 7″ baytrail windows tablets, one battery died and i’m pissed that they can’t Turn on and just run corded to the wall… I saved the battery circuit board from the puffy cell, but a replacement battery for a no-name tablet like this is about 20.00 . For 80.00 $ I can get this generations Cherry Trail with 2gb ram, 32gb storage, Win10 / Android dual boot, 8″ screen, new 14-nanometer process, USB-C … thats what I want.!

    But my Old 1gb ram , 16gb hd , 7″ win10 baytrail tablet is a wonderful magical thing, I love it.. It’s my DAILY PC, I wish I could Just hot glue a 12′ USB power cable to the one with the bad battery. Perfect bed side tablet, and without a battery feather light and safe.

    Can someone hack the old Baytrail Motherboards found on these tablets to boot without a battery??

        1. Internal tablet batteries are ‘smart’ though and report their state, including charge and temperature and ‘good’ status. Which is the whole issue I gather.

          1. They’re smart only with high-end tablets, and even then it’s mostly not the case. With cheap tech (like the one @bop mentioned) you’ll be lucky to have a thermistor pin – gosh, just look at the photo for this article, even this reference phot has only V+ and GND, no thermistor pin connected! So if he takes a good (low-impedance) DC-DC set on 4.2V and powers it from a good PSU, things will be OK. Some say he could power it from 5V, but IMO the charger controller IC might burn up.

          2. Laptops have “smart” batteries, and in most cases it’s easy to either use some special software (expensive to obtain, but there are alternative sources if you know, what I mean) to reprogram the chip or directly rewrite EEPROM with proper values used by controller. Newer battery controllers require NDA’s to read their datasheets with all the magic numbers and formulae needed, but older ones are so obsolete, that their datasheets are available online, and reprogramming them is easy…

          3. I was replying to a guy talking about another generic baytrail tablet, one which won’t work without a battery present, which to me indicates that one has a ‘smart’ battery. (else you could just attach any old battery to fool it, even a few AA’s.)
            That the one from the article only has two wires is therefore not too relevant.

    1. I’m not sure if it applies in your case, but some manufacturers (I’m thinking old electronic calculators) used the battery as a “load” or “voltage regulator” while running off the wall charger. Running without a working battery could fry the circuits…This makes more sense when you realize that a 4.5 volt battery pack was often charged from a cheap charger at 7.5 (or higher) voltage.

      Excuse me, I have to go chase some kids off my lawn…

    2. Disable the battery ‘smartness’ in the BIOS? They report their state but I think you can disable it ‘Boot on invalid battery’ is a setting you can disable on some tablets for instance.
      Or maybe you can take the control circuitry out of the defective battery and trick that into thinking it has a battery. Be careful with messing with those batteries though, they burn easily and fiercely.

      1. So did you try changing the setting in the BIOS? Although I looked it up and the BIOS of that tablet has ‘boot on invalid battery?’ set to ‘enabled’ by default.
        However it has another 7 or 8 setting related to the battery, so there’s stuff to try.
        An example is that it has a setting “VBattery threshold’ which is set to ‘3700’, although I have no idea what that setting is about at this point, you’d have to do a web search.

  6. Reminds me of a Linksys NAS200 that I hacked a few years ago. It ran an 80386 clone but Linksys provided the source code and a working build system. It wasn’t difficult to hack, but the designers had taken some shortcuts with the Redboot boot loader. If you were just playing around via the serial port, you’d quickly find out that you there was a non-standard command to flash the BIOS, but it expected you to download an image to a specific RAM location via TFTP first and didn’t bother to warn you if you didn’t do that. So yeah, I bricked it less than a week after I bought it.

    Fortunately in a dark corner of the Web, I found a development tool that was only supposed to be available under NDA. I had to build a JTAG connector but I got it to work again. Not that I used it much because it was slow as think crap through a funnel and it didn’t provide enough ventilation for the hard disks. But still a nice learning experience, and 15 minutes of fame :)

    ===Jac

  7. Same thing happend to me a while ago with a Z3735F tv box. Was dicking around with bios settings and ended with a soft brick.
    Reflash back to the factory image fixed it, just like OP

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