Yes, personally, I have encountered this behavior several times: the wiring, just one wire that fails is enough.
But, let's go in parts:
1) Please share some photos of the way you have the 20 pin flat cable connected to your teensy
I checked the additions in GDSTx for the BT817-7" screen, using the 5" BT817 screen and to my surprise it works very well, even though the dimensions of the screen in theory are 800x480, internally the BT817 chip easily supports the...
@Turby: The BT817 chip in 7" screens corrects the problem of non-square pixels.
This is the timmimg table, left: 7", right: 5"
#define SizeEVE 74
Share us some pictures of your TFT (by the way: my next BT817!, yeah!)
It's good to know that you chose this type of screen, you really went to the top of this type of TFT's: 7" is really quite a challenge.
The BT817 chip should work without problems, it seems to me that the times between the 5" BT817 with which I...