Tool/software:
I use the AM243X Industrial COMMS SDK 09.02.00.09 and I found the LwIP interface source code for ICSS-EMAC doesn't support concatenated pbuf.
In the file am243x-mcu-plus-sdk\source\networking\icss_emac\lwipif\src\lwip2icss_emac.c the transmit function Lwip2Emac_sendTxPackets gets a pbuf as argument but it ignores if it is a concatenated object
In order to have the LwIP stack working properly, there must be a define in lwipopts.h
#define LWIP_NETIF_TX_SINGLE_PBUF 1
