Sunday Geek Project: Raspberry Pi NTP Server Recipe

To setup each Raspberry Pi 2 as a Stratum 1 NTP server I’m following the recipe created by David Taylor. While the recipe is very thorough and complete, I ran into an issue disabling the login prompt on the Raspberry Pi’s serial port under Debian Jessie. No matter what I did the login prompt would always be re-enabled after the Pi rebooted. This resulted in GPSD not starting correctly. Read on to find out how to resolve the issue.I found the solution in this post on the Raspberry Pi forum at StackExchange. In summary:

1. Execute the following commands:

   sudo systemctl stop serial-getty@ttyAMA0.service
   sudo systemctl disable serial-getty@ttyAMA0.service
   sudo systemctl mask serial-getty@ttyAMA0.service

2. Then run the configuration program sudo raspi-config:
   1. Select option “9 – Advanced Options”
   2. Select option “A7 – Serial”
   3. Select “No”.
   4. Select “Okay”.
   5. This will return you to the main menu, select “<Finish>”.
   6. You will then be asked if you would like to reboot your Pi. Select “<No>”.
3. Then you will need to edit the file /etc/boot.txt with your favorite text editor and add or change the following line:

   enable_uart=1

4. Now you can reboot your Pi.

This should ensure that the login prompt is disabled on the serial port.