Yes, you're right, the Due is hard-configured for little-endian. I mis-remembered, as I have not used a Due in many years. But the rest still holds - the endian-ness of ARM processors is selectable, and has been for 20+ years, going all the way back to the "Thumb" processors of the '90s. That includes the current CORTEX-M series, which, unlike earlier versions, allow endian-ness can only be configured when the processor logic is synthesized during the chip design process. Earlier models allowed endian-ness to be configured at run-time, usually via a configuration pin.