As stated in the topic's subject, I am currently trying to expose I2C2 (The 
I2C bus that's normally connected to P9_19, P9_20) to pins P9_21 and P9_22. 
Since the documentation for the Beaglebone Black/Green show that pins 21 
and 22 can be used for I2C2 it must be possible, I just can't find a solid 
way to do it.

*Background Info*

Hardware: Seeed BeagleBone Green
OS: debian
uname -a: Linux beaglebone 3.8.13-bone71.1 #1 SMP Wed May 20 20:13:27 PDT 
2015 armv7l GNU/Linux
(Note that I am willing to flash whatever OS/kernel version it takes to get 
this working)

The requirement comes from an error I made not knowing about the default 
I2C device tree settings for the device. Since there were two pairs of I2C2 
pins listed in the documentation, I chose the pair that lad less overlap, 
which was a mistake. I have since then fixed the error in my 
schematic/board but I already have demo PCBs on the way from the fabhouse. 
It'd be great to just expose those pins to the I2C bus rather than cut and 
rewire traces manually. Sadly due to the time constraints for the project 
(Deadline is on the 31st) I cannot send out for an updated PCB.

The software side of this project is based on the Adafruit_BBIO library 
which is, in turn, based on the python smbus library. There's very little 
in terms of configuration when setting up I2C communication with those 
libraries so the magic switch is most likely not there.

*Main Methods Attempted*

For all cases, assume that the UART2 device tree overlay has been disabled 
via blacklisting in uEnv.txt and a reboot.


   - bonescript pinMode() - Does nothing to the mode of the pin in this 
   case although getPinMode() does show that I2C2_SDA/SCL is a possible mode 
   option.


   - Enabling an I2C2 device tree overlay from the bb.org-overlays 
   
<https://github.com/RobertCNelson/bb.org-overlays/blob/master/src/arm/BB-I2C2-0A00.dts>
 
   repo that I edited to point to P9_21 and P9_22 
   <http://pastebin.com/vc06hVC1> instead of the normal I2C2 pins. This 
   compiles and shows up in the cape manager after inclusion but nothing 
   happens on pins P9_21 and P9_22 when I try to communicate to my PCA9685 
   devboard. Meanwhile pins P9_19, P9_20 work just fine so the bus is still 
   functional.


   - Tried Bernhard Tittelbach's lovely Device-Tree Overlay Generator 
   
<http://kilobaser.com/blog/2014-07-28-beaglebone-black-devicetreeoverlay-generator#dtogenerator>to
 
   make a setting file for each pin.


   - Mucked around with the Universal Cape overlay but it never really 
   seemed to change any pin states in this case.
   

*Summary*

Given any possible (supported) OS, how can I get pins P9_21 and P9_22 into 
the correct pin mode to mux to the I2C2 device?
And is it possible to have I2C2 exposed on both P9_19,20 and P9_21,22?

Lastly, I apologize for any confusing nomenclature. I've been flashing 
different OS versions and reading documentation relevant to differing 
flavors of debian trying to solve this that I'm a bit number-dizzy.

Thanks for your time!

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