I will be cross posting from http://ourl.ca/6018
I am taking my first few steps into the world of hacking and have made it my project to get this device to run custom software

So far i have been collecting information on it, here is what i have:
the screen is 98x68 pixels and supports 65K colors
it has 16 MB memory
it has a speaker
it can be connected to a computer via usb
the processor is most likely a clone of the 6502 microprocessor
a 6502 runs at 2 MHz

links with more info:
some generic info
Good info on LCD and stuff
I think there are 8 of these in parallel
this is the display

my long term goal is to be able to put custom software on it
any help would be greatly appreciated :)

also: $2 on amazon for one of these it looks like
http://www.amazon.com/Rock-Monsterz-Roc-MIUCHIZ-Companions/dp/B000F901FA/ref=pd_sim_t_1

Here's a site for some general hand-held hacking knowledge: http://web.archive.org/web/20071028090324/www.bripro.com/low/gameking/index.php

For that price, I might have to check out one of these myself! This reminds me of Ben's recent work with hacking that imGo (?) device, so I'm sure he'll have some sage words of advice for you. I hope you'll keep us posted on your progress!

I sure hope that Amazon.com ships those mudkipz... er... I mean miuchiz handhelds outside USA, because I searched for the exact same name on the canadian site and it wasn't available.

Ditto for me. I might have to follow you up on this once I see some progress

here are the pics of the innards http://s534.photobucket.com/albums/ee348/Miotatsu/miuchiz/
sorry for the watermark and i know you cant see too much from those, i will draw it all out too

So I see a speaker in the bottom-right corner, the black and red wires to the battery case, a single IC with high-density pins in the center (what's the numbering on that IC?), a bubble-type IC that is probably the processor (which would make me think that the proper IC is RAM or ROM), a ribbon connector at the bottom, presumably to the LCD, and a thick blue wire (antenna? is there some kind of wireless communication capability in this thing?).

*cough*tiemulator*cough*

oh the thick blue wire goes to a male USB, the battery casing is above the device in these pictures. the USB connector is strapped to the battery casing and normally can be pulled out of the device from a hole in the case on the side. It also has some kind of infared sensor or something at the top but i dont know much about that.
The thing in the center to the right of the blob is one of these:
http://www.sst.com/products/?inode=41433
the number on it confirms it

Note that that's a 16M*b* chip, or 2MB, not a 16M*B* device.

Indeed, i was fully aware of that and have been quite confused for a while now, because linux is able to see the device fine and it reports it as being 16 MB, NOT 16 Mb, i can get you a log in a sec if you like

until i opened the device up i assumed it had 8 of them inside it btw, but it only looks like one from what i see

Comparing 6502 and Z80 clock speeds won't mean much; the 6502 had a simple internal design and very efficient instruction set meaning it could do a more per clock cycle than other CPUs of the time (hence the generally slower clock speed of 6502 machines than comparable Z80 machines).

I suspect that reverse engineering the device from the hardware is going to be virtually impossible due to the black epoxy blob that hides the CPU. If you can find a way to dump the ROM (I'm not sure if that will be possible over USB - you say the device shows up as a mass storage device?) you should be able to disassemble that, which would hopefully give you a better idea of how to control the hardware and from there write your own software.

The IM-me is a different story; the ICs inside the unit and its USB adaptor are unobscured and are easily identifiable microcontrollers. The company that designed the IM-me even kindly included a debug port in the battery compartment!

Disk /dev/sdc: 16 MB, 16384000 bytes
1 heads, 32 sectors/track, 1000 cylinders
Units = cylinders of 32 * 512 = 16384 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x11ad0412

Disk /dev/sdc doesn't contain a valid partition table


Benryves: thank you for the info, i will start looking into how i could go about dumping the ROM

I'm not a Linux user, I'm afraid, but is there a way you could extract a raw disk image from that? My suspicion is that the device pretends to be a disk drive so that the firmware can be updated by writing a new disk image to it, but as the firmware is just a blob of executable code and data this won't look like a file system to the host OS.

I'm a little puzzled by the 1000 cylinders figure, though. That doesn't add up to me.

Code:
should do the trick.

The thing that doesn't make sense to me is it acting like 16MB. Looking at the datasheet, it looks like a 2MB storage device.

for clarification the chip has exactly the following on it:
SST
39VF1681
70-4C--EKE
0623151-D

I assume you cant attach files on cemetech, but i will be posting the ROM dump on Omnimaga in an attachment, the file is around 16 MB large.

I have uploaded it to my site as well, you can get it here

havent flashed to it yet, but here is the demo of the device in action including the test mode which i was not aware of until today

Test modes are always exciting. Did you get any more leads on what kind of processor this has under the epoxy blob, or how you can do stuff to its firmware?