Reading GRAM (Graphic Memory) from ILI9341 SPI TFT

Someone tried that? Any code example? Datasheet says it is possible but I cannot find any example code for arduino.

Seems like a less commonly required feature for most people. There may not be anybody who has tried it.
Your best bet is to read the library code you are using and the datasheet. With a little bit of effort, you should be able to add the functionality to the library yourself.

Its pretty common not to pin out the MISO pin for the SPI interface, or to buffer the parallel interface
in one direction only. You’ll have to figure out if the hardware you are using allows reads. There are many
different displays using the ILI9341 and similar chips, and they differ in which interfaces are brought out.

(Normally there’s no need to read back from a display, you know what’s there!)

MarkT:
Its pretty common not to pin out the MISO pin for the SPI interface, or to buffer the parallel interface
in one direction only. You’ll have to figure out if the hardware you are using allows reads.

That is extremely useful information. You could otherwise burn hours wondering why it isn’t working.