I have been doing a bit of research (in advance of getting my hackable dingoo). I can pretty much bet the farm that the device address is *not* 0. From what I have read, the device ID should be 0xEC if you are writing to the chip and 0xED if you are reading from the chip.
See page 3 of : http://www.chrontel.com/pdf/an98.pdf
That lists the address for the 7023 but it may also work on the 7024. It doesn't make much difference... In a few days I will have my logic analyzer hooked up to the I2C bus and then we will know what the CPU sends/recvs. from the chip. And I was right in assuming that the bus speed is slow. It is 400khz max so my 100mhz analyzer is kinda overkill but that is okay.
The bad news is that I know nothing about the LCD screen. I do know that the CPU has 2 different LCD controllers in it. If these are the controllers that we need to manipulate, we should be able to do that. One is a Smart controller so I think these are, indeed, the ones we are talking about. I have several datasheets and appnotes to read but this is the kind of stuff I read all the time
Also, I would love to find a "real" version of the 7024's datasheet. I put in a request but I highly doubt it will go anywhere...
And, btw, there is no way DD is going to tell you anything about the firmware. The firmware is made by ChinaChip and unless dingoo owns them, they won't have access to the source. I would bet that is how it works but I could be wrong.
I got the real datasheet for the 7024 encoder! Also, the 0xEC/0xED above is stated as 0x76 (7bit address) in some of the literature. If you shift that left one, you get 0xEC/0xED with the R/W bit...
I will have to find a place to upload the datasheet tomorrow.