Oh and fyi for anyone with the same chip, you also want to:- #undef LWIP_RAM_HEAP_POINTER in lwipopts.h- Increase the stack size of the default task in the FREERTOS settings, I set mine 512 words, you might be able to get away with less by experiment...

Had the same problem on stm32f767 trying to use LWIP with CMSISv2. I narrowed the problem down to erroneous data being written to the "TxPktSemaphore" Semaphores being used by the LWIP library. Turns out its because the assigned stack for the tasks a...