Please refer to the following TF-A BL2 boot flow
a. BL2 initializes the DRAM, configures TZASC
b. BL2 loads BL31, BL32, and BL33 images to the DDR memory after validating these images BL31, BL32, and BL33 images form FIP image, fip.bin.
c. Post validation of all the components of the FIP image, BL2 passes execution control to the EL3 runtime firmware image named as “BL31".
Because there is problem at DDR controller initialization, so it is impossible to load BL31, BL32, and BL33 images to the DDR memory.