Adafruit 16x2 LCD doesn't turn on with Pine64

[pfeerick]

i can see from your print-out of the i2c registers that it is not detecting the address of the LCD.  How are you powering it?  Double check your connections.  Make sure its on the correct bus...

Mark, I think you need to have a another look at the first post, specifically the picture... you can clearly see the LCD is on a Adafruit LCD Pi Plate, meaning it is i2c, with all comms and power coming from the pi bus. Plus, there is no room for incorrect wiring as assembly is as simply as place LCD here and solder connectors, etc. 

My question here would be does I2C work out of the box with a particular debian or ubuntu image, and if not, what configuration is needed to get it up and running?

You are incorrect; on all counts.  

The PI bus on the PineA64 is not compatible with the Raspberry PI .  By definition, the connections of the ada fruit hat are incorrect.

I think you need to read the post ahead of yours....

...  again, I will re-iterate, this project is not going to be plug and play.

I'm referring to you asking about how the display is connected, as per post #2 above. There was no need to scare about 5v bidirectional logic (which is not normally the case, unless you are reading back from the LCD, when RW is grounded, the IO is one way), as this is not so with the Adafruit Pi Plate. It also explains how the backlight is powered. And as per the post above, the connections are correct, simply that the pine64 doesn't have the pullups on the i2c bus that the rPi does. 

If you only care about the display, the only connections that need to work are 3 (SDA), 4 (5v), 5 (GND) & 6 (SCL)? Are telling me that those most basic of connections are not compatible (bearing in mind that the pullups are indeed missing - which is a bit of an oopsie... considering they made provision for 2k pullups in the schematic and on the board - but just didn't populate the components).

And I'll ask again: Does I2C work out of the box with a particular debian or ubuntu image, and if not, what configuration is needed to get it up and running?

Edit: Nevermind. After adding a 2K pullup to the 3 & 5, pulling them up to 3.3v (note, 3.3v, NOT 5v, so pin 1), the pine64 detects a device attached at addr 20. Without the pullups, a device is NOT detected. This is on a debian image, running kernel 3.10.102-3-pine64-longsleep, and no special configuration done to enable or otherwise configure the I2C. Simply the installation of the i2c-tools package.

Code:

pfeerick@pine64:~$ sudo i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: 20 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --