Dec 162011
 

Yes, I’ve joined this century and bought myself a tablet. Lately, I’ve found myself needing some means of navigating in strange areas whilst on the bicycle, and while pieces of paper work — if you’re organised enough to print them out in advance and not ride too fast (otherwise they disappear with the wind), I’ve found there are a number of shortcomings with this.

Since I like open source, and didn’t like the idea of spending several hundred on a hand-held GPS with proprietary firmware & map data which I need to constantly purchase updates for, I opted for the cheapskate route.  I picked up a GL4Ever Flytouch III Tablet off eBay.  The unit I have came loaded with Android 2.3 (Gingerbread).

Ultimately I may replace the OS, or at least, the kernel, soon as I have sources for it, but in the meantime, it runs what it came with.  I have however, already managed to gain root access.

Those who might do a search for how to do so, may come across this guide.  I tried this first, and found I had no joy.  USB Debugging was enabled out-of-the-box on the unit I have, but z4root did not successfully enable root access.  The following are my notes on how I gained a shell with root access on the device.  Ohh, and I warn you, there is no warranty given in the instructions below.  If it breaks, you get to keep the pieces.

  1. Download and install Gingerbreak.
  2. Run Gingerbreak, it will run for a while, before resetting the device.  Upon starting, you should now notice you have a Superuser application installed.
  3. Next, install Android Terminal.
  4. Now, run /system/bin/su.

/bin/su is a symbolic link to /bin/busybox which was installed without the setuid bit, and is broken anyway, you’ll find if you do add a setuid bit, it will report that it can’t find the ‘root‘ user.  This system has no /etc/passwd or equivalent user database, so it has no idea who ‘root‘ is, but it knows who UID 0 is, and that’s what matters.  The latter ‘su‘ you’ll find has the necessary permissions, and knows about UID 0.

Other things I’ve found… the operating system lurks on a SD card embedded in the device.  Or at least, it’s presented as a SD card; /dev/block/mmcblk0.  The user-accessible SD-card port is /dev/block/mmcblk1.  You can verify this by ejecting the card, doing a ls /dev/block, then inserting a card and repeating.

On my TODO list, is to make a DD-copy of this block device, and pick through to see how one swaps out the kernel.  I’ll post notes if I figure this out.  I am also yet to obtain the kernel sources, I’ll chase those up before long.