Possibly useful for others too, a PDF with GPIO header pinouts and their logical mappings (as seen from Linux 3.17-rc, don't know about older kernels), for the A20-oLinuXino-LIME and probably also the A10-oLinuXino-LIME, but I don't have one of those.
Did some testing but I'm sure there must be mistakes in there.
https://docs.google.com/file/d/0B-6ABBpYc3P3ZElDSjY2R1Jzc0k (https://docs.google.com/file/d/0B-6ABBpYc3P3ZElDSjY2R1Jzc0k)
There seems to be an error in the manual (as mentioned in an A10 thread on this forum): GPIO-2 pins 17 thru 39 seem wrong.
Best, -Bert Lindner