Portenta H7 SDRAM errors

So the most recent platform version is 15.6.0 using ArduinoCore-mbed 4.0.2 per releases.

Let’s go for the low hanging fruit first and equalize the used Arduino core version. To do a quick update, open a PlatformIO core CLI and do

pio pkg update -g -p ststm32

and retry uploading the PlatformIO sketch.