Hi Vinit,
Please try the following to switch IBL from LE to BE and check if you can get BOOTP packet from DSP when using ROM Ethernet boot mode.
Steps to flash IBL can be found from http://processors.wiki.ti.com/index.php/BIOS_MCSDK_2.0_User_Guide#IBL.
Please note that the steps here are written for little endian. Because of this, we need to use big endian .bin and .out file from [bios_mcsdk install dir]\tools\boot_loader\ibl\src\make\bin folder. The eeprom writer .out file under [bios_mcsdk install dir]\tools\writer\eeprom\evmc6678l\bin is in LE mode, and therefore needs to be rebuilt for BE. Instructions for rebuilding eeprom writer can be found from [bios_mcsdk install dir]\tools\writer\eeprom\docs\README under "Steps to re-build eepromwriter".
When doing the flash, please ensure dip switch 3 is set for Big Endian (http://processors.wiki.ti.com/index.php/TMDXEVM6678L_EVM_Hardware_Setup#Hardware_Setup_Steps)
After the IBL is switched to BE, please set the switch settings to ROM Ethernet Boot mode (with Big Endian). http://processors.wiki.ti.com/index.php/TMDXEVM6678L_EVM_Hardware_Setup#Boot_Mode_Dip_Switch_Settings. Then, power cycle DSP and check if there is BOOTP packet coming from DSP.
Thanks,
Hongmei