SD2Flash2BootAVRHex not working on Arduino Mega ADK (2560)

[proasnet]

Dear @JAndrassy ,
I am trying example from ArduinoOTA Library SD2Flash2BootAVRHex.ino for update program in Arduino Mega ADK, with Ethernet Shield.

1. Downloaded your myboard - ok
2. Files from folder myboard copied to hardware folder of Arduino - ok
3. Selected Arduino Mega 2560 (Optiboot) - ok
4. Bootloader loaded to Arduino ADK - ok
5. Return to select Arduino Mega ADK as board - ok ( is right? )
6. Upload example sketch - ok
7. Blink LED example export as hex from Arduino IDE and copy as update.hex to a SD card - ok
8. To a while loop, I added a Serial.print("."); to see loops of copy

    while (hexFile.available() && !ihex2binError) {
      Serial.print(".");
      int length = hexFile.readBytesUntil('\n', buffer, sizeof(buffer));
      lineNumber++;
      ihex_read_bytes(&ihex, buffer, length);
    }

9. Example is not working. I see in console periodically

12:50:39.578 -> Initializing SD card...
12:50:39.578 -> Update HEX file found. Performing update...
12:50:39.578 -> 
12:50:39.578 -> .

That see, that only the first loop was executed.
Please help me for run an update.
Thank you