Hi,
I'm testing a batch of 'HDMI 5" Display Backpack - Without Touch' we received earlier this year.
We did noticed that lastest OS on Raspberry Pi 4 does not allow to display any image on the TFT (absolutely nothing, backlight doesn't seems activated).
We also used an external power supply for the TFT to be sure that the TFT was powered @ Pi 4 boot time... still nothing.
The config.txt has been modified modified accordingly to the tutorial (including audio output and hdmi_drive=2)... still nothing.
The TFT are however running on older Pi version (older version of the OS on Pi 2 (I have under the hand).
So I'm figuring a configuration issue regarding the new video driver of the Pi 4.