Hello, I purchased an old, used, working tablet based on obsolete processor WM8505. Why an obsolete model ? The reason is very simple : there is, on the internet, a full datasheet of the processor and good documentation, in general. When new products reach the market, they are still very technical, so well documented and simple to use. When it goes to be a business, the “commercials” come in and say to technicians : “you must hide all the infos and introduce some strange key to make impossible for anyone to look inside”. This is ‘cause the “commercials” are not able to produce ideas, they are able just to speak about things they can’t understand, and always have blinded vision of the future. Someone, any time, breaks the locks and looks inside, ‘cause the “perfect lock” doesn’t exists. The result of this stupid behaviour is that the mankind is slowered and uses 20 years to reach the results that can be achieved in two. But the “commercials” are so happy, they sell and make big business. Absolutely haven’t a long view into the future.
Ok, I opened my tablet, just for look what’s inside. Here is a picture :
Just in the middle, you can see the “coreboard”, the hearth of the system, with the processor, the SPI flash with boot program, the ram, the oscillators and … the NAND FLASH ? I can’t see the NAND flash, the “hard disk” of my tablet. Where is the NAND flash ?
ooooh, I found it, Is on a small board, hidden under the main board. But… there are only four wires ! Naaah, the NAND flash is a very common USB memory key ! That’s incredible, so the boot program in SPI flash is able to launch the system from an USB memory… VERY interesting !
I decided to disconnect the module from the tablet and wire it to a standard USB plug, in order to analyze it with my PC.
So, now I have an USB memory key with the hard disk of my tablet… Immediatly put in my PC and use the program Win32 Disk Imager, it’s open source, it’s simple, it works very well. I create a copy (img) of full pendrive and saved to disk for cloning on another USB memory key. Obviously, for using a standard usb memory key, I mounted a female usb plug in the tablet, using the 4 wires where was attached the original board. I used a 4GB memory key as destination of image file and tried to restart my tablet with such pendrive…
Ok, wires are connected, try to boot the tablet :
Uhmmm, animation starts, but continues “ad libitum” without starting the Android OS. There must be something wrong. Now, I extracted my pendrive and put it in another PC, running Puppy Linux. This is for a simple reason, Puppy Linux is my favourite “distro” and has the great GParted program, a powerful application to “look” inside disks and partitions. Inserting the pendrive, I discovered that has MANY partitions inside !
I see the main partition (the start) hasn’t the ‘boot’ flag. May be that’s the reason for tablet not starting ? Mmhh, let’s try to check. Modified the flags adding the ‘bootable’ to the first partition, then extracted the pendrive and tried again on the tablet…
WOW, now it works ! Ok, now, coming back to the Puppy Linux, I looked at all the partitions and the contents. First, the partitions list:
and now, the contents of each one : first SDB1
and, finally, the SDB8
This is our “localDisk” ! Now, the original NAND flash was 2 GB and I have the new one that is 4GB, so i will resize the partition, using the GParted going from this situation :
to this new organization, filling all available space :
OK, all done. Now back again to the tablet and reboot. The led lights, the system starts…
And now, let’s go to measure how big is our LocalDisk 🙂
Wow… very good. Now, I can’t have an USB memory key attached to my tablet, so I opened the pendrive’s case and discovered that the small board inside is VERY similar to the original one…
So, I desoldered the USB plug and soldered the new circuit in place of the old one. All worked perfectly, tablet closed, disk space doubled.