I am developing a project for ethernet communication using lwip stack with vdk on my custom board with blackfin processor bf527. I am using lwip_sysboot_threadtype.c from the blackfin example project FileServerStdio. I am using already developed functions for writing and reading from ethernet FS_write() and FS_read() respectively. The problem is I am not able to transfer more than around 400 bytes using FS_write() in one function call. Even when make multiple calls to the write function sometimes it transfers, sometimes not. I want to transfer a data block of 4096/or 8192 bytes. Please guide how to resolve this?