IMX6ul custom board booting issue

[Shivasagar_myana]

Dear all,
i have been facing a issue with booting of imx6l custom board, the changes in the hardware is,we used 128MB DDR3L instead of 512MB and 8GB eMMC in the place of uscdh2.
for this the changes we did changes in the uboot is,
In file include/configs/mx6ul_14x14_evk.h
CONFIG_SYS_MMC_ENV_DEV change 1 to 0
CONFIG_MMCROOT change to "/dev/mmcblk0p2"
PHYS_SDRAM_SIZE SZ_128M

we tested DDR calibation and updated in file imximage.cfg, we attached file of DDR calibartion values.and we updated the below reg values
Write leveling calibration
MMDC_MPWLDECTRL0 ch0 (0x021b080c) = 0x00010000
Read DQS Gating calibration
MPDGCTRL0 PHY0 (0x021b083c) = 0x414C0154
MPDGCTRL1 PHY0 (0x021b0840) = 0x00000000
Read calibration
MPRDDLCTL PHY0 (0x021b0848) = 0x40405052
Write calibration
MPWRDLCTL PHY0 (0x021b0850) = 0x40404E48

** other than this anything we need to change in the uboot ?

the problem is sometimes we are able to booting and sometimes it is hanging (at multiple location on different power cycle)in the middle of booting and some times it is giving kernel panic. i attached all the logs and dmesg log in below. 
we tested voltages, and power sequences,Reset circuit and sequence all are working as per the data sheet.

Can anyone give the solution for this ?

[igorpadykov]

Hi Shivasagar

for 128MB memory example one can look at 128MB DART-6UL :
https://variwiki.com/index.php?title=DART-6UL_Yocto&release=RELEASE_ZEUS_V1.2_DART-6UL
https://variwiki.com/index.php?title=DART-6UL_128MB_DRAM
"14 DDR size and Contiguous Memory Allocator"
https://variwiki.com/index.php?title=VAR-SOM-MX6_Yocto_Fido_R1#DDR_size_and_Contiguous_Memory_Alloca...

Best regards
igor

[Shivasagar_myana]

Hi igor,

       Thank you for your response, we changed "cma=32" in uboot now it is booting,but still some times it is hanging (for example if we try for 10 times for 2 times it is failing).

Could you please let us know if any modifications to be done for achieving 100% success rate.

Thank you,

Looking forward to hear from you.

[igorpadykov]

one can try to change drive strength of emmc signals as described on

https://community.nxp.com/t5/i-MX-Processors/eMMC-8GB-to-4GB-crash-on-linux-yocto-boot/m-p/373231

Best regards
igor