A source code bug creates issues when operating in Vertical memory access mode.

[moeur]

RE: Adafruit_SSD1306.cpp
A bug the in source code of the Adafruit_SSD1306 class in the display() method on line 1000

While attempting to set the page range an invalid page end value of 0xFF is used.
This does not create problems while the memory access mode is Horizontal, but creates big problems when operating in Vertical memory access mode. A proper end page value must be used in this case.

-moeur