imx6d boot fail with emmc 5.0

[allen_kim1]

Dear all,

Our customer uses eMMC5.0 device. ( IMX6D , android 5.0  , sandisk emmc sdin9dw4-16g  ) 

we already modified android source ( mmc.c file  : card->ext_csd.rev )

first sample is ok , mfgtool downloading is ok ,  android boot is ok

our customer made almost 1k board

1st : 360 ea board : 27 ea board has problem

2nd : 300 ea board : 6 ea board has problem , customer changed SMT factory

3rd : 500 ea board : around 10 ea

• problem 

board didn't boot ( uboot message is not shown  ) , not always can't boot , sometime board can boot ok 

approximately 1 time can't boot ( total 10 times tried ) , but boot fail is not regular ( randomly )

• they think problem follow CPU IC

1 bad cpu reball to normal board  --> not boot

2 new cpu swapped on problem board  -> OK boot

• I guess below first action is not done in problem board  ( therefore ram initialize is fail and uboot message is not displayed )

        booting process

1. boot rom read DCD table from emmc
2. boot rom initilize RAM with  DCD table 
3. boot rom copy uboot binary to ram from emmc
4. uboot message display on serial terminal

my Question

is there any compatibility with emmc 5.0 device ? they use sandisk .

scope picture 

1 is POR , 2 is SD4_DATA0

abnormal boot 

normal boot

May I have advice?

Best Regards,

[igorpadykov]

Hi Allen

emmc5.0 should work fine as boot ROM will fall back to the eMMC4.4

standard when a emmc5.0 capable device is detected. Please try to extend POR

up to 0.8-sec, considering ERR009678

http://cache.freescale.com/files/32bit/doc/errata/IMX6DQCE.pdf 

Also one can check why in abnormal boot case there is toggling SD4_DATA0 before POR

release - this may be power-up issue or bad power for eMMC (check its reset) or from

some external attached device. Check power supplies with oscilloscope, paying attention

to XX_CAP voltages. Use guidelines from i.MX6 System Development User’s Guide (rev.2, 10/2016)

http://cache.freescale.com/files/32bit/doc/user_guide/IMX6DQ6SDLHDG.pdf

Best regards
igor
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