I used the CubeMX 4.18 to do a simple LwIP UDP server project for the STM32F746-Discovery board. It works well for the default configuration. But If the LwIP MEM_SIZE is increased for 64K bytes or more, or if a buffer with 64K bytes or more is created. The Ethernet don't work anymore, neither for reception or for transmittion.
Anyone have any idea about the cause of this issue?