Hello
We are currently working on a custom i.MX8 board which at the moment boots from manufacturing mode: It boots from the SD card if present and does a fallback to serial download if SD card is empty or not present. All this works fine. But we want to change default boot device to an eMMC present on the board. I understand that this can be done by blowing fuses and have a pretty good idea on how to do that. But before we start blowing fuses it is important that we can force the board back to serial download mode (or from the SD card) if e.g. an error occurs.
Seems that this should be possible using the BOOT_MODE0 and BOOT_MODE1 pins. But configuring these two pins forcing the board into Serial Download does not seem to work. The board simply does not boot using that configuration and no NXP usb device is shown on host computer. This configuration works fine using the i.MX8 EVK so really strange why we can't do this on our custom board..
A better option would be to configure BOOT_MODE0 and BOOT_MODE1 to "Internal Boot" and use GPIOs to override fuse settings. But unfortunately the required GPIOs is not accessible and used for other purposes.
Is there a way to find out why we can't force the board into "Serial Downloader" mode? Or perhaps something else we can try to make this work?
It is important that we can get back to manufacturing mode if we by accident brick the board during development.
Any suggestions is much appreciated
Thanks in advance,
Esben
