RPi 3.5 inch LCD white screen when STM32 is defined in User_Setup.h

[alw1746]

I have a clone RPi 3.5" LCD display connected over SPI to an STM32L432 running TFT_eSPI. graphics_test sketch works fine
though a bit slow. However when STM32 is defined in User_Setup.h, I get a flickering white screen but the serial output
did show it running faster. I repeated the experiment with a blue pill and had the same outcome.

Could it be an interference issue at higher speed given I'm using a breadboard with dupont jumper leads? I have the same wiring with an ESP8266 and the display worked perfectly at a high frame rate. The touch_controller_demo worked as well. I lowered SPI_FREQUENCY to 10Mhz without success. I'm wondering if there is perhaps an issue with the optimised processor support(I'm assuming it involves DMA). Any suggestion on what else I can try to diagnose this problem much appreciated. Pls see attached text file for more info.

info.txt