I am writing my own custom library for the SH1106 132×64 display. From this datasheet I would gather, leaving all the various configurations as default, that page 0 would be at the top of the display.
It however never specifies that in writing. There is only a table on page 16 (Figure. 8) that would suggests that.

I tried multiple displays and they all had page 0 at the bottom. I also tried various combinations of all the different addressing modes but none solved the issue.

I then tried to display something using the Adafruit SSD1306 library and that put page 0 at the top.

What the heck is wrong here?

HEADER FILE

#define SH1106_WIDTH 132
#define SH1106_HEIGHT 64

#define SH1106_COMMAND 0x00
#define SH1106_DATA 0x40

#define DISPLAY_OFF 0xAE
#define DISPLAY_ON_NORMAL_MODE 0xAF
#define DISPLAY_ON_RAM_CONTENT 0xA4
#define DISPLAY_ON_RAM_IGNORE 0xA5

#define SET_DISPLAY_NORMAL 0xA6
#define SET_DISPLAY_INVERSE 0xA7

#define SET_CONTRAST_CONTROL 0x81

#define SET_MEMORY_ADDRESSING_MODE 0x20

#define SET_DISPLAY_START_LINE 0x40 // Allowed Values: 0x40 to 0x7F, Reset Value: 0x40 / x100 0000

#define SET_PAGE_ADDRESS_FOR_PAGE_ADDRESSING_MODE 0xB0
#define SET_COM_OUTPUT_SCAN_DIRECTION_NORMAL_MODE 0xC0
#define SET_COM_OUTPUT_SCAN_DIRECTION_REMAPPED_MODE 0xC8

#define SET_SEGMENT_REMAP_SEG0_0 0xA0
#define SET_SEGMENT_REMAP_SEG0_131 0xA1

#define SET_MULTIPLEX_RATIO 0xA8
#define SET_DISPLAY_OFFSET 0xD3

#define SET_DISPLAY_CLOCK_DIVIDE_RATIO 0xD5
#define SET_PRECHARGE_PERIOD 0xD9

#define SET_COM_PINS_HARDWARE_CONFIGURATION 0xDA
#define SET_VCOMH_DESELECT_LEVEL 0xDB

#define CHARGE_PUMP_SETTING 0x8D

#define DEACTIVATE_SCROLL 0x2E

C FILE

uint8_t dynamicInitDataArray[] = {
  SH1106_COMMAND, DISPLAY_OFF,
  SH1106_COMMAND, SET_MULTIPLEX_RATIO, 0x3F,                     // Reset Value: 0x3F / xx11 1111
  SH1106_COMMAND, SET_DISPLAY_OFFSET, 0x00,                      // No Offset
  SH1106_COMMAND, SET_DISPLAY_START_LINE,
  SH1106_COMMAND, SET_SEGMENT_REMAP_SEG0_131,
  SH1106_COMMAND, SET_COM_OUTPUT_SCAN_DIRECTION_NORMAL_MODE,
  SH1106_COMMAND, SET_COM_PINS_HARDWARE_CONFIGURATION, 0x12,     // 0x02 or 0x12 (POR)

  SH1106_COMMAND, SET_CONTRAST_CONTROL, 0x7F,
  SH1106_COMMAND, SET_DISPLAY_CLOCK_DIVIDE_RATIO, 0xA0,          // Suggested Ratio: 0x80
  SH1106_COMMAND, CHARGE_PUMP_SETTING, 0x14,                     // Enable: 0x14, Disable: 0x10

  SH1106_COMMAND, SET_MEMORY_ADDRESSING_MODE, 0x02,              // Horizontal: 0x00, Vertical: 0x01, Page: 0x02
  SH1106_COMMAND, SET_PRECHARGE_PERIOD, 0x22,
  SH1106_COMMAND, SET_VCOMH_DESELECT_LEVEL, 0x20,
  SH1106_COMMAND, SET_DISPLAY_NORMAL,
  SH1106_COMMAND, DISPLAY_ON_RAM_CONTENT,
  SH1106_COMMAND, DEACTIVATE_SCROLL
};

/**
  * @brief This function initializes the display.
  * @param *hi2c:         i2c-handle pointer
  * @param deviceAddress: i2c device address
  */
void SH1106_Init(I2C_HandleTypeDef *hi2c, uint8_t deviceAddress) {
  size_t totalBytesToTransmit = sizeof(dynamicInitDataArray)
    / sizeof(dynamicInitDataArray[0]);
  HAL_I2C_Master_Transmit(hi2c, deviceAddress, dynamicInitDataArray,
    totalBytesToTransmit, 1000);
}

/**
  * @brief This function sets the page.
  * @param *hi2c:         i2c-handle pointer
  * @param deviceAddress: i2c device address
  * @param page:          page number from 0-7
  */
void SH1106_Set_Page_Address(I2C_HandleTypeDef *hi2c, uint8_t deviceAddress, uint8_t page) {
  if(page > 7) {
    return; // Check if page is in bounds.
  }
  uint8_t setPageAddress[2] = {SH1106_COMMAND, SET_PAGE_ADDRESS_FOR_PAGE_ADDRESSING_MODE + page};
  HAL_I2C_Master_Transmit(hi2c, deviceAddress, setPageAddress, 2, 1000);
}