Is it possible (on the i.mx8 mini) to override the BOOT_MODE pins (via code/register write) to enable the Serial Downloader (without having to physically change the boot-pins)
No, it is not possible to override the BOOT_MODE[1:0] settings in software without physically switching the BOOT_MODE[1:0] pins.
iMX7's u-boot's bmode usb command writes to gpr9 and gpr10 (general purpose registers). The same register on the imx8m mini's reference manual states these are "reserved for internal use"...
Can you please check with the i.mx8 team if these still exists but are not documented.
The R&D have confirmed that there is no way to override the boot mode settings in software.
Retrieving data ...