Data recovery from a broken android tablet (aka Everything with a CPU has a serial port!)

Some weeks ago I destroyed my tablet, let’s say “by mistake”. I actually destroyed the display first, and then the connector from the motherboard (the one and only board in the tablet) and the LCD.

The tablet itself was nothing special (~100€) so I’m almost glad I can now  look for a better one, would I need it (…I really did not…).

Namely it’s a TrekStor SurfTab (ST10216-2).

So, no problem at all… except… WTF! The files inside it! …well, files that are not SO important (in that case I would have saved them somewhere else of course) but still, manuals and application notes that would be boring to recollect.

But, as Plato used to say: Everything that has a CPU on which some flavour of linux is running, MUST have a console serial port!

So I started looking for some probe-contacts (probably used with some sort of pogo-pins during the early life of my tablet) and discovered where the console serial port is (pretty easily, they are near the CPU); so I share some pictures:

serialtablet

And:

serialtablet2

It turns out it’s a LOW VOLTAGE (i.e.: 3.3V, DO NOT attach it to a standard RS232 port) serial port running at 115200bps.

After attaching it to a 3.3V USB-Serial adapter and powering (I detached the battery and powered it through the battery contacts with a bench PSU), that’s what my terminal showed:

screenshot

And after issuing the su command, I’m root inside my tablet.

Nice 🙂

Now I can finish destroying the rest of the tablet.

PS.: OK, on my device I found that the cp command is not available, but I discovered that busybox is, so the command to use is busybox cp <src> <dest> (…it even accepts wildcards!, found it here); in particular I used the sdcard to tranfer all valuable data.

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