Stacking packaging technology is widely used in wafer factories to package 2 ~ 8 or more bare dies together. The common marking method is the number of bare wafers plus CE (Chip Enabling). For example, 2CE is two bare wafers with the same capacity packaged together.

The board of 903 is not cheap.

And very few.

Those with motherboards have changed their shells.

I suggest you just disassemble the phone and sell the screen, the shell, the keypad and so on. It's worth it.

One of my 903 motherboards is worn out, and the other parts are sold at 1000 RMB.