Oled Display turn upside down

Most libraries can use different rotations e.g. u8glib documentation

Likewise, any library extended from Adafruit_GFX can do setRotation() in software.
Hardware libraries generally provide their own setRotation() that uses the hardware.

I am not familiar with your library. It looks as if it inherits from Adafruit_GFX i.e. it provides setRotation() but does not do any hardware rotation. From a brief glance at the SSD1306, it does not look as if you can reverse the vertical direction.

David.

Here is code from my SSD1306 library to flip the display 180 degrees:

if (bFlip) // rotate display 180
{
uc[0] = 0; // command
uc[1] = 0xa0;
I2CWrite(oled_addr, uc, 2);
uc[1] = 0xc0;
I2CWrite(oled_addr, uc, 2);
}