eMMC not detected on iMX8M mini SBC

[peter_gabor]

SBC with iMX8M mini, 2GB LPDDR4, 16GB MIcron eMMC(MTFC16GAKAEJP-4M). Boot mode set to internal boot, CFG for eMMC boot, the same as on NXP EVK (Wifi on SD1, SD card on SD2, eMMC on SD3 ) Some boards work ok, some occasionally(10-20%) refuse to boot from eMMC, although this is already programmed and working before.

Norml boot - from eMMC

U-Boot SPL 2019.04-imx_v2019.04_4.19.35_1.0.0+g85bdcc7 (Sep 09 2020 - 09:39:53 +0000)
power_bd71837_init
DDRINFO: start DRAM init
DDRINFO:ddrphy calibration done
DDRINFO: ddrmix config done
Normal Boot
Trying to boot from MMC2

U-Boot 2019.04-imx_v2019.04_4.19.35_1.0.0+g85bdcc7 (Sep 09 2020 - 09:39:53 +0000)

CPU: Freescale i.MX8MMQ rev1.0 1600 MHz (running at 1200 MHz)
CPU: Industrial temperature grade (-40C to 105C) at 48C
Reset cause: POR
Model: Eurotech Reliagate-10-14 board
DRAM: 2 GiB
tcpc_init: Can't find device id=0x52
setup_typec: tcpc port2 init failed, err=-19
setup_typec: tcpc port1 init failed, err=-62
MMC: FSL_SDHC: 1, FSL_SDHC: 2
Loading Environment from MMC... OK
No panel detected: default to MIPI2HDMI
adv7535_init: Can't find device id=0x3d, on bus 1
Display: MIPI2HDMI (1920x1080)
Video: 1920x1080x24
In: serial
Out: serial
Err: serial

BuildInfo:
- ATF f92d379
- U-Boot 2019.04-imx_v2019.04_4.19.35_1.0.0+g85bdcc7

flash target is MMC:2
Net: eth0: ethernet@30be0000
Fastboot: Normal
Normal Boot
Autoboot in 2 seconds type stop to interrupt
Saving Environment to MMC... Writing to MMC(2)... OK
switch to partitions #0, OK
mmc2(part 0) is current device
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
24334848 bytes read in 294 ms (78.9 MiB/s)
40243 bytes read in 4 ms (9.6 MiB/s)
## Flattened Device Tree blob at 43000000
Booting using the fdt blob at 0x43000000
Loading Device Tree to 00000000aa512000, end 00000000aa51ed32 ... OK

Starting kernel ...

eMMC must not be detected, because console is empty, if it fails. If SD card inserted, due to  error occurring during the internal boot, the boot code jumps to the Serial DownloaderBefore going into USB serial mode, Boot ROM detect SD/MMC card on USDHC2 port. If a card is inserted, ROM will try to boot from it. This is the so-called Manufacture SD/MMC boot.

Console in case, eMMC is not detected 

U-Boot SPL 2019.04-imx_v2019.04_4.19.35_1.0.0+g85bdcc7 (Sep 09 2020 - 09:39:53 +0000)
power_bd71837_init
DDRINFO: start DRAM init
DDRINFO:ddrphy calibration done
DDRINFO: ddrmix config done
Normal Boot
Trying to boot from MMC1

U-Boot 2019.04-imx_v2019.04_4.19.35_1.0.0+g85bdcc7 (Sep 09 2020 - 09:39:53 +0000)

CPU: Freescale i.MX8MMQ rev1.0 1600 MHz (running at 1200 MHz)
CPU: Industrial temperature grade (-40C to 105C) at 34C
Reset cause: POR
Model: Eurotech Reliagate-10-14 board
DRAM: 2 GiB
tcpc_init: Can't find device id=0x52
setup_typec: tcpc port2 init failed, err=-19
setup_typec: tcpc port1 init failed, err=-62
MMC: FSL_SDHC: 1, FSL_SDHC: 2
Loading Environment from MMC... OK
No panel detected: default to MIPI2HDMI
adv7535_init: Can't find device id=0x3d, on bus 1
Display: MIPI2HDMI (1920x1080)
Video: 1920x1080x24
In: serial
Out: serial
Err: serial

BuildInfo:
- ATF f92d379
- U-Boot 2019.04-imx_v2019.04_4.19.35_1.0.0+g85bdcc7

flash target is MMC:2
Net: eth0: ethernet@30be0000
Fastboot: Normal
Normal Boot
Autoboot in 2 seconds type stop to interrupt
switch to partitions #0, OK
mmc1 is current device
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
24334848 bytes read in 1028 ms (22.6 MiB/s)
40243 bytes read in 8 ms (4.8 MiB/s)
## Flattened Device Tree blob at 43000000
Booting using the fdt blob at 0x43000000
Loading Device Tree to 00000000aa512000, end 00000000aa51ed32 ... OK

Starting kernel ...

Is there any explanation for such a behaviour? PCB layout must be good, once board boots from eMMC, it never ever fails anymore, all stress tests always pass.

Regards

Peter

[igorpadykov]

Hi peter_gabor

this may be related to drive strength, similar issue described on

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

One can try to tweak "USDHC pad setting override" described in Table 6-19. USDHC boot eFUSE descriptions  i.MX 8M Mini Applications Processor Reference Manual

Best regards
igor