Yes, this is something not clear.

In one of my previous posts, I mentionned that I cabled the data lines according to the AE support. They say it has to be connected something like D7 = DB0, D6 = DB1 and so on.

But, as you say, I can't believe it is correct; it looks to be reversed. Logically, D4 is connected to DB0 (B0), D5 to DB1 (B1) and so on.

Until now, I'm testing every program modification with both configuration of data lines since absolutely nothing appears on the display.

Another thing: I have two (alsmost ) same displays. One is 2x16 and the second is a 3x16 one. I swap them too just to make sure both react the same.

MCLR, DATA and CLOCK lines from the programmer are physically disconnected from the circuit after the burning process.

I'll recable this with different colours this afternoon and with the "logical" data bus lines way.