We want to customize the board based on i.mx8mq with LPDDR4 4GB but it failed to boot with 4GB configuration in u-boot.
Here are the codes that we updated:
In this header file: uboot-imx/include/configs/imx8mq_evk.h
Changed from #define PHYS_SDRAM_SIZE 0xC0000000 to #define PHYS_SDRAM_SIZE 0x100000000
And in this folder: uboot-imx/board/freescale/imx8mq_evk/ddr
Replaced ddr_init.c and ddrphy_train.c by files generated from MSCALE DDR Tool for 4GB RAM.
It would be appreciated if you could give some idea about anywhere else to update.
Note: It worked fine with 2GB RAM.