Using two i2c OLED's problem

Projects Programming
1

Hi,
I have been trying to run two SSD1306_128X64 OLED's using the code I found on the forum but only manage to display on one (0x78) though I do know that the other OLED (0x7A) is addressable and works OK when used separately using another library.
I intended to use two Oled's using one Ardunio Nano.
Not sure why it does not works as it is mentioned that the code works perfectly OK...any help please.

#include "U8glib.h"

U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_NONE); 
extern uint8_t I2C_SLA;
uint8_t I2C_SLA = 0x7A;
boolean redraw_display_one = false;
boolean redraw_display_two = false;

void setup()
{
  I2C_SLA = 0x078;
  u8g.firstPage();
  do
  {
    draw_message_one();
  }
  while(u8g.nextPage());

  delay(10);

  I2C_SLA = 0x07A; 
  u8g.firstPage();
  do
  {
    draw_message_two();
  }
  while(u8g.nextPage());
}

void loop()
{
  if (redraw_display_one)
  {
    I2C_SLA = 0x078;

    u8g.firstPage();
    do
    {
      draw_message_two();
    }
    while(u8g.nextPage());

    redraw_display_one = false;
  }

  if (redraw_display_two)
  {
    I2C_SLA = 0x07A;
    u8g.firstPage(); 
    do
    {
      draw_message_one();
    }
    while(u8g.nextPage());
    redraw_display_two = false;
  }
  
  unsigned long time = millis();
  
  if (time > 5000 && time < 5033)
  {
    redraw_display_one = true;
    redraw_display_two = true;
  }
}

void draw_message_one()
{
  u8g.setFont(u8g_font_fub20);
  u8g.drawStr(12, 28, "Hello");
  u8g.drawStr(12, 58, "World");
}

void draw_message_two()
{
  u8g.setFont(u8g_font_fub20);
  u8g.drawStr(12, 28, "Goodbye");
  u8g.drawStr(12, 58, "World");
}
2

With both connected, have you run the I2C scanner sketch, to determine that they both are found?

Not sure why it does not works as it is mentioned that the code works perfectly OK

That statement is self-contradictory. Either it works because the code is perfect, or it doesn't work because the code is not perfect.