Uboot crashes on 1 imx6ul board but not on another

[RayC]

On one of our imx6ulevk like board (very similar to imx6ulevk), it crashes in u-boot immediately, on another board it boots normally to linux.

"Bad" board:

================================================== 

U-Boot 2020.04-5.4.70-2.3.0+ge42dee801e (Apr 07 2021 - 18:52:22 +0000)

CPU: i.MX6UL rev1.2 528 MHz (running at 396 MHz)
CPU: Commercial temperature grade (0C to 95C) at 42C
Reset cause: POR
Model: Freescale i.MX6 UltraLite 14x14 EVK Board
Board: MX6UL 14x14 EVK
DRAM: 512 MiB
MMC: FSL_SDHC: 0, FSL_SDHC: 1
Loading Environment from MMC... *** Warning - bad CRC, using default environment

[*]-Video Link 0 (480 x 272)
[0] lcdif@21c8000, video
In: serial
Out: serial
Err: serial
switch to partitions #0, OK
mmc1 is current device
flash target is MMC:1
Net: Could not get PHY for FEC1: addr 1
Could not get PHY for FEC1: addr 1
Get shared mii bus on ethernet@2188000

Error: ethernet@2188000 address not set.
Get shared mii bus on ethernet@2188000
undefined instruction
pc : [<00000088>] lr : [<9ee99377>]
reloc pc : [<e898b088>] lr : [<87824377>]
sp : 9de6a7b8 ip : 00000020 fp : 00000017
r10: 9de91680 r9 : 9de72ed0 r8 : 9de744b8
r7 : 9de74458 r6 : 9f90b3c2 r5 : 00000004 r4 : 9de92588
r3 : 00000048 r2 : 00000006 r1 : 00000004 r0 : 9de92588
Flags: nzCv IRQs off FIQs off Mode SVC_32
Code: 00000000 00000000 00000012 20296328 (79706f43)
Resetting CPU ...

Good board with the same SD card:

==========================================================

U-Boot 2020.04-5.4.70-2.3.0+ge42dee801e (Apr 07 2021 - 18:52:22 +0000)

CPU: i.MX6UL rev1.2 528 MHz (running at 396 MHz)
CPU: Commercial temperature grade (0C to 95C) at 35C
Reset cause: POR
Model: Freescale i.MX6 UltraLite 14x14 EVK Board
Board: MX6UL 14x14 EVK
DRAM: 512 MiB
MMC: FSL_SDHC: 0, FSL_SDHC: 1
Loading Environment from MMC... *** Warning - bad CRC, using default environment

[*]-Video Link 0 (480 x 272)
[0] lcdif@21c8000, video
In: serial
Out: serial
Err: serial
switch to partitions #0, OK
mmc1 is current device
flash target is MMC:1
Net: Could not get PHY for FEC1: addr 1
Could not get PHY for FEC1: addr 1
Get shared mii bus on ethernet@2188000

Warning: ethernet@2188000 using MAC address from ROM
eth0: ethernet@2188000
Fastboot: Normal
Normal Boot

....

Any ideas?

Thanks,

Ray

===================================

[vijayaragavansr]

hi ,

Similar problem is faced in imx6ul board with latest kernel.

what is the solution?

Anyone found?

below is the UBoot Log

U-Boot 2020.04-5.4.70-2.3.0+ge42dee801e (May 31 2021 - 09:39:40 +0000)

CPU: i.MX6UL rev1.1 528 MHz (running at 396 MHz)
CPU: Commercial temperature grade (0C to 95C) at 52C
Reset cause: POR
Board: MELANGE SYSTEMS - SBC
DRAM: 512 MiB
MMC: FSL_SDHC: 0, FSL_SDHC: 1
Loading Environment from MMC... *** Warning - bad CRC, using default environment

[*]-Video Link 0 (480 x 272)
[0] lcdif@21c8000, video
In: serial
Out: serial
Err: serial
switch to partitions #0, OK
mmc1 is current device
flash target is MMC:1
Net: Could not get PHY for FEC1: addr 1
Could not get PHY for FEC1: addr 1
Get shared mii bus on ethernet@2188000

Error: ethernet@2188000 address not set.
Get shared mii bus on ethernet@2188000
undefined instruction
pc : [<00000088>] lr : [<9ee99377>]
reloc pc : [<e898b088>] lr : [<87824377>]
sp : 9de6a7d8 ip : 00000020 fp : 00000017
r10: 9de91680 r9 : 9de72ed0 r8 : 9de744b8
r7 : 9de74458 r6 : 9f90b3c2 r5 : 00000004 r4 : 9de92588
r3 : 00000048 r2 : 00000006 r1 : 00000004 r0 : 9de92588
Flags: nzCv IRQs off FIQs off Mode SVC_32
Code: 00000000 00000000 00000011 20296328 (79706f43)
Resetting CPU ...

Thanks

Vijay

[RayC]

See my post below.

I worked around this by setting the MAC address fuse words (using an earlier u-boot and the u-boot "fuse" command.).

If someone has a u-boot patch that lets you boot up, please let us know.

[igorpadykov]

Hi Ray

had board passed ddr test, in general

reason may be poor soldering, one can try to replace chip.

Best regards
igor

[RayC · Accepted solution]

Hi Igor,

Turned out the "bad" board can be "fixed" by fusing the OTP MAC address (Bank 4, words 2-4).

Also an older kernel and u-boot (version 4.9.88) boots up on all boards with or without a MAC address.

That led me to believe the new kernel and u-boot (version 5.4.70_2.3.0 Zeus) is sensitive to a 0:0:0:0:0:0 MAC address.

Maybe it's not really a crash but just an ASSERT in the new u-boot code? Has anyone else seen similar problems?

Thanks,

Ray  

[RayC]

Thank you, Igor.

Strangely, a much older image (4.9 kernel, 4.9 device tree) boots up even on the "bad" board.

Is it possible some (5.4.70 kernel) device tree setting may have caused this?

Since I am not very familiar with the processor, I am more than a little puzzled.

How do I read the "Code"?  All I can see is there's an invalid instruction. pc is at 88, I suppose this is very early on in u-boot.

Thanks,

Ray

undefined instruction
pc : [<00000088>] lr : [<9ee99377>]
reloc pc : [<e898b088>] lr : [<87824377>]
sp : 9de6a7b8 ip : 00000020 fp : 00000017
r10: 9de91680 r9 : 9de72ed0 r8 : 9de744b8
r7 : 9de74458 r6 : 9f90b3c2 r5 : 00000004 r4 : 9de92588
r3 : 00000048 r2 : 00000006 r1 : 00000004 r0 : 9de92588
Flags: nzCv IRQs off FIQs off Mode SVC_32
Code: 00000000 00000000 00000012 20296328 (79706f43)
Resetting CPU ...