When the Early I/O release feature is enabled, there may be an occasion where HPS DDR calibration fails after peripheral RBF file is configured on Intel® Arria® 10 SX devices such as 270/320/480. When this happens, Uboot prints out a message as shown below.
Error: Could Not Calibrate SDRAM
If this problem occurs, please try to use a cdratio value other than 8 when configuring periph.rbf. Using cdratio=4 is recommended. If it fails again, then try cdratio=2 and cdratio=1. Set cdratio=8 when configuring core.rbf. These changes can be done in /uboot-socfpga/arch/arm/cpu/armv7/socfpga_arria10/fpga_manager.c or /u-boot-socfpga/drivers/fpga/socfpga_arria10.c.