Adafruit FONA SIM800H GSM module sleep ok, won't wake up

Other Hardware 3rd Party Boards
1

As the title say I can successfully put the GSM module of the Adafruit Fona to sleep with either AT+CSCLK=1 or AT+CSCLK=2. After that, the only way to wake it up is by a reset. It does not respond to:

  1. DSR put low for like 50-100 ms for sleep command AT+CSCLK=1

or

  1. Any AT command for sleep command AT+CSCLK=2

For 1 above:
#define FONA_DTR 5
void pulseDTR()
{
digitalWrite(FONA_DTR, HIGH);
delay(10);
digitalWrite(FONA_DTR, LOW);
delay(70);
digitalWrite(FONA_DTR, HIGH);
}