ARM processors are actually "bi-endian". They will operate big-endian, little-endian, or both, depending on how the processor logic is configured when the chip is designed. The design package you receive from ARM supports either, or both. So, there is no "one" endian-ness with ARM. The "endian-ness" affects ONLY the bus-interface and address mapping logic of the processor, which are a tiny, tiny part of the overall processor logic. The vast majority of the ARM-based chips I've designed and used over the last 20 years were implemented as big-endian, including the Due, which is the ARM I have used most recently.