In this post I shall explain  how to recover a non responsive XBEE modem.

I’ve an USB XBEE adapter on which a S1 PRO modem is plugged on.

When I tried to reconfigure a S1 PRO (802.15.4) Modem , it went unresponsive.Any attempt to write Firmware failed & Recovery process was unsuccessful.


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Before starting the Recovery process I understood that I’ve to Optimize the USB – Serial port settings so that the PC can respond to the XBEE USB adapter. An XBEE USB adapter uses a FTDI chip .By default the FTDI drivers have a latency time of 16msec  & Transmit/Receive size  of 4096 Bytes.

The PC doesn’t get the Bytes fast enough to respond to the Serial device , before it times out.So any attempt to recover or update an XBEE on USB adapter may fail.

To optimize the port settings I opened the Device Manager & Right clicked the USB Serial port where the USB adapter is connected & selected Properties.


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Under Port Settings Tab I clicked on Advanced..

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& Changed the Receive as well as Transmit Bytes to the lowest one 64 from the drop down list.

I Set the Latency Timer to the lowest possible i.e.,  1


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Clicked  OK & closed the Device Manager.

Now I pulled out the Modem from the USB adapter.

I confirmed that ,under Modem configuration of XCTU , correct type of Modem is selected.Mine is S1 PRO ,so I selected XBP24 & confirmed that firmware is XBEE PRO 802.15.4 . I selected the latest version 10ED.

I check marked ‘Always Update Firmware’ & clicked Show Defaults.

Now I clicked Write button (note that XBEE is not yet plugged on to the USB adapter).

A new INFO window appeared requesting action.

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At this point I plugged on the S1 module on to the XBEE USB adapter with Reset button kept pressed.Care was taken to confirm that pin 10 goes to GND & pin 1 to supply.

Now I released the Reset button to see the Reprogramming in Action.

The Modem has been successfully recovered & Test/Query operation in XCTU recognizes the Modem.

Watch the recovery procedure in video below :