>> Definetly i think that Morphos developpers aren't working on an architecture move

> DIdn't they announce they were working on something?

No. The most substantial "something" they "announced" in this regard was 3 years ago, but they didn't say they were already working on it. They hadn't even decided for the target architecture yet.

https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=8121&forum=9&start=18

> Samsung used to have their hardware reference manuals on line. You might still be able
> to get them.

Yes, they have them publicly available mostly, even for an Exynos 5 chip:

http://www.samsung.com/global/business/semiconductor/file/product/Exynos_5_Dual_User_Manaul_Public_REV100-0.pdf

> IIRC Allwinner are also considered to be open source friendly.

Allwinner SoCs use Cortex-A8, Cortex-A7 or Cortex-A15, of which only the last one would be worth supporting in my opinion. Unfortunately, Allwinner SoCs with Cortex-A15 CPU core use PowerVR GPU, for which documentation is said to be hard to come by for non-corporate developers.