This is vidisha and my aim is also same to program TM4C129EXL which has TM4C129ENCPDT using Ethernet Flash based bootloader.
Your's is Flash based bootloader or Rom based?
For Flash based i used code of DK-TM4C129EX i.e boot_emac_flash and could program it also but during uploading of any application code it shows me "attempting to connect"
I used your code and it worked for me but only once , i mean i can't upload the application code for second time.
Plz if u have code for Flash based ethernet bootloader and it's demo code plzzz share with me..i need it urgentl