AW: Booting verdin-imx8mm_defconfig fails

[Traut Manuel LCPF-CH]

Hi Marc,

Thanks for your quick reply.

>> I am not sure if I built/using u-boot as intended for this platform.
>
> I would advice to stick to the documentation [1].

Thanks for the reference.

>> 1) running via serial download:
>> Please note that we never integrated/validated USB device support on Verdin iMX8M Mini (and Plus for that matter). So one really can NOT use UUU with upstream U-Boot so far and does have to stick to what we document.

Thanks for the clarification. I am aware of this and added this just for reference to see that generally the SPL seems to work.
I worked on this a couple of months ago [3] - however the base-address of the controller needs to be retrieved somehow in the probe function. Here it was just hardcoded.

>> 2) running from SDCard:
>
> As all our SoMs are factory fused to boot from their on-module eMMC storage one can NOT boot them from an SD card.

Thanks for the information. I thought SDCard boot might work, cause of the following found in [4]
--8<--
Important: make sure that there is no bootable SD card plugged into the slot. Otherwise, the 
module will try to boot from the external SD card instead of going into the USB serial loader.
--8<--

>> 3) running from eMMC:
>
> Please stick to the documentation and skip 2 blocks when writing to the first hardware area boot partition.

Thanks - this helps. However it seems that the SPL build with the defconfig expects the 2nd stage u-boot from mmc 1 instead of 0
--8<--
U-Boot SPL 2023.04+dfsg-1+iris+manut4 (May 03 2023 - 12:16:03 +0000)
WDT:   Started watchdog at 30280000 with servicing every 1000ms (60s timeout)
Trying to boot from MMC1
--8<--
Guess I get this fixed on my own. 

> If anything goes wrong the boot ROM usually falls back to serial download mode. There are ways to look at what exactly you may have done wrong see e.g. [2].[Traut Manuel LCPF-CH] 

Oh, this really eases debugging. Thanks for the reference!

Thanks
Manuel

[1] https://source.denx.de/u-boot/u-boot/-/blob/master/doc/board/toradex/verdin-imx8mm.rst
[2] https://www.nxp.com/webapp/Download?colCode=AN12853
[3] https://www.mail-archive.com/u-boot@lists.denx.de/msg437039.html
[4] https://docs.toradex.com/108681-verdin-imx8m-mini-datasheet-v1.1