Please confirm you have done the DDR validation with the QCVS DDR on the customer board with correct DDR clock.
QCVS_DDR_User_Guide
And please confirm the parameters could pass the "Diagnose connection"
In fact, if you could connect the CodeWarrior TAP, you could program the flash follow the C:\Freescale\CW4NET_v2020.06\CW_ARMv8\ARMv8\Help\PDF\ARMv8_Targeting_Manual
8.6 Board Recovery
Thanks