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From hardware revision R3C the PA1 offers a recovery feature allowing you to flash the device with a new PA1 firmware.

IMPORTANT: The PA1 recovery procedure can apply only on hardware revision >= R3C. The revision number can be found on the sticker on the back of the PA1.

Needed tools:

The PA1 can boot in a recovery mode. In this mode it will boot with a hardcoded Class C ( /24 ) IP address of When the PA1 is in recovery mode the device will download the firmware file via TFTP from the IP address

If you are unfamiliar with TFTP please take a look at this article for more information:  Reset a phone to factory defaults or reset all settings


  1. Isolate the PA1 from your normal network so that it will not try and obtain an IP address via DHCP
  2. Configure your Laptop or PC with the static IP address, with a 24 bit mask of There is no need to configure DNS or a default gateway address.
  3. Connect your PC to the the same PA1 network
  4. Make sure the TFTP server is running, listening on port 69 and snomPA1.bin is at the root of the shared TFTP directory.
  5. Connect the KBD wiring cable to the KBD I/O port of the PA1.
  6. Shorten pin 0 (blue wire) and pin 1 (white wire) by connecting them together.
  7. While the pins are shortened, connect the PA1 to the PoE Switch plug the power adapter.
  8. After some seconds the TFTP transfer will begin. You can disconnect the short after about 20 seconds after the PA1 boots up.
  9. While the rescue is progressing the following LED control sequence can be observed:
      • Contacting TFTP-server and fetching the rescue file: red LED - ON, green LED – ON
      • Erasing the flash: red LED - FLASHING (about 1Hz), green LED - FLASHING (about 1Hz)
      • Writing to flash: red LED - FLASHING (faster than 1Hz), green LED - FLASHING (faster than 1Hz)
      • Rescue successful: red LED - OFF, green LED - ON (stays like that, no reboot)
      • Rescue failed (file corrupt or erasing/writing failed): red LED - ON, green LED – OFF

  • Once the recovery procedure is complete (red LED - OFF, green LED – ON) connect the PA1 back to your normal network. Log in and confirm the recovery procedure was successful.
  • If the recovery failed (red LED - ON, green LED – OFF) try the procedure again or contact Snom Support for further assistance.