berni_: The first differene is that the first one is working well with Adafruit and UTFT (GEEK24 model selected). The 2nd is not working at all.
... We certainly cannot guess what you are using. Care to post all the required libraries you used? UTFT is a large library suited to several displays, micro-controllers and pinouts, even with the right model selected, there are different pinouts, plus we dont know if you are using an uno, a mega or anything in between.
berni_: Below some pictures that shows differences and similarities. Same manufacturer mcufriend.com. The not working display seems to have a different controler. It answer 7777 when adafruit library is checking the model. On le left: the NOT WORKING display, on the right, the display is OK
I have both and you are right the display is different, but it still complies with the ST778x command set as described on previous posts. As far as i know they are not supported by UTFT, however it may be that one of the LCD's has an extended command set, for example, some are known to be compatible with ILI9325. I have no idea what controller the GEEK24 model uses, this should be your first mystery to be solved - why are you using it and who told you it would be compatible?