I know that this is a very old question but after more than two months, I'm really sad... I'm developing a work (for scientific research) using a stm32f746igt mcu (from waveshare 746i) with several middleware/peripherals (freeRTOS, stemwin, usb hid, uart, spi, i2c, adc, timers, TFT controlled by fcm, etc...). Everything works absolutely OK, (including some DMA process). Trying to move stemwin to external SDRAM, the process hangs in GUI_Init (alloc / unlock) with a bus fault or at a first attempt to create a window (no problem in GUI_Init in this case) with a usage fault (invalid state). The different kind of fault, is not correlated with changes in software but sometimes seems to be dependent on the rebuild process, i.e. compiling the same code, the fault type can change... I'm using TrueStudio. I tried to configure everything (fmc config, timings, MPU, cache...) performing almost know memory tests (read/write, 8, 16, 32 bit aligment, integrity of the physical memory) and, (obviously) all perfect (including using large amount of data - up to 512K). At this point, I give up. The only thing that I wish to know (because after seen hundreds of discussions in specific forums I still have no precise idea) is if effectively someone was successful in put this "thing" (stemwin) working without any problem in external sdram. Thanks.