-is documented in the diagram in https://www.udoo.org/docs-x86II/Introduction/Introduction.html
-The other is based on the hardware manual https://udoo.org/download/files/UDOO_X86/Doc/UDOO_X86II_MANUAL.pdf
+is documented in the diagram and text for linux version later than 4.15 in:
+https://www.udoo.org/docs-x86II/Introduction/Introduction.html
+The other is based on the hardware manual:
+https://udoo.org/download/files/UDOO_X86/Doc/UDOO_X86II_MANUAL.pdf