Sorry for taking your time, but i'm lost. I'm new to both iMX and U-Boot, therefore a mistake might be visible to professionals like you.
We have built a system closely resembling i.MX8M-evk board, which we have trouble properly booting up. To boot it up we have started with cloning a U-Boot official git repository. In order to build a binary we have followed https://u-boot.readthedocs.io/en/latest/board/freescale/imx8mm_evk.html example with gcc-aarch64 compiler and several device tree changes: instead of uart2 we are using uart1 (unsuccessfully) and several other i2c changes. The image was prepared to be used within a board-internal flash memory or an emmc.
! Except the very last step:
# dd if=flash.bin of=/dev/sd[x] bs=1024 seek=33 conv=notrunc
The first build had a misconfigured i2c device (several devices took same address: pmic and port expander), which did not boot up a pmic properly. Second build actually corrected that mistake and we were able to boot up and use "UUU"-tility to play around with a binary. I'm guessing that mcu clocks and an I2C have booted up properly. But there were no signals on either uart lines (we have changed "used" console device to uart1), so no U-Boot startup message was shown.
Then we have added the above mentioned line to a build process (i had doubts about it since the beginning), and a new upload through uuu-tility rendered the device useless. We only had 2 boards, so no way to check a new firmware now, until we manufacture an another batch. We had no jtag capabilities before and uuu does not recognize a device from now on. I understand that the above mentioned line was aimed at an external sd card. A blank space of 33 kilobytes? why not 32? We also had to add 0x55AA sequence in order for the rufus to recognize the image.
Another question is: the above mentioned line lists 33 kB length blank space, but several binaries (like from a similar verdin board, presented in a u-boot repository) have a different blank space at the beginning - 3.3kB. Please point me in the right direction: am i using an outdated tutorial or are there other factors at play?
Hi Pavel
what processor used in the case, i.MX8MQ or i.MX8M Mini (these are different).
Recommended to use uboot from nxp source.codeaurora.org/external/imx/ repository:
https://source.codeaurora.org/external/imx/uboot-imx/tree/board/freescale/imx8mq_evk?h=lf_v2021.04
https://source.codeaurora.org/external/imx/uboot-imx/tree/board/freescale/imx8mm_evk?h=lf_v2021.04
and use attached documents.
Best regards
igor