I don’t want to load the freeRTOS via j-tag . I’ve Compiled the RTOS through the EDK but want to load the elf file through uboot. Can I load and run it from uboot ? I know I need to change the ld script by removing the STARTUP DIRECTIVE and to change the ENTRY from _boot to _start, but where is the _start resides if any ? where is the RTOS entry point ?

FreeRTOS is probably not the entry point of your system. It is linked with your application, which will take care of calling the appropriate FreeRTOS runtime subprograms. How would you do it if your application was not linked with FreeRTOS? Once you have the answer, do the very same thing and you’re done. Same thing for uboot vs. JTAG.