On 7/27/13, Steve Markgraf <steve(a)steve-m.de> wrote: Found it, thanks. Yeah, the differences do seem big indeed. While I was searching around for an SPCA552E datasheet, I found this: http://www.download.revosupport.com/scp2009_download_folder!/BONUS%20MEMBER… On page 12 of that schematic there's our lovely Sunplus chip. Of course it's a totally different phone, but at least we can see what are the pin interfaces coming off this chip. In the above schematic, we see that SPCA552E connects to just the host CPU, the LCM and the camera - no frills. But the 554 datasheet you've found describes a much more complex device - adds USB, audio, mass storage... Were you ever able to figure out just how the backlight works on this display? Your code has a comment about a particular register in the SPCA supposedly turning the BL on or off, but looking at the pin interfaces of this SPCA in the Nokia schematic, I don't see anything even remotely related to the backlight... Yet the original firmware is able to not only turn this BL on and off at will, but also change the brightness - during calls, the display dims instead of blanking completely. On a related note, were you ever able to figure out the pinout of the 30-pin flex between the main PCB and the LCM? If this pinout were known, I could probably trace out the stuff of interest to me (like the backlight) on the main PCB using your layer pictures, but if I have to reverse-eng the LCM itself, that might be a bit above my skill level. :( Bummer. But just out of curiosity, how did you figure out that it's an 8051? Did you see the original phone fw pushing something to the SPCA that looked like 8051 instructions? FWIW, the 554 datasheet describes its CPU as a "32-bit RISC processor" - too closed to even name what it is! Kim