floresta:
As far as your other problem goes - you appear to be having trouble with your LCD DB7 line (pin 14), it is always low. This may be a problem with your soldering or with your breadboard.Don
I've changed that wire on DB7 to new wire and it's the same. I don't use breadbord for the screen, screen is connected directly to Arduino. I also tried to connect DB7 to different pin on Arduino (and change the pin number in code of course) but with no result. I also don't think that the problem is that DB7 is always low. When I connected DB7 to GND I also couldn't get these "h" and other letters, but I wasn't having 40 white rectangles on the screen. When I connected DB7 to GND instead of this symbols which don't work the screen displayed other symbols like "p", "q" etc. When DB7 is connected to Arduino (pin 12 in my case) then instead of any symbols the screen displayed 40 white rectangles. So the LCD doesn't behave like DB7 pin is always low I think...