Converting an array of uint8_t to a char array
When you cast as char *, println thinks you are passing it a string. It will try to print it as a string and stop on the first 0x00.

You can use Serial.write to send the array as integers (no conversion):

Serial.write(data, sizeof(data));


If you want to send the ASCII representation of these numbers, use a loop. Serial.print will convert:

int count = sizeof(data) / sizeof(data[0]);
for (int i = 0; i &lt; count; i++) {
    Serial.print(data[i]);
}
Serial.println();