Multitech MultiConnect xDot Developer's Manual page 18

FOTA
If the Dot was able to reconstruct the file using parity fragments, it sends a CRC check to the Conduit.
Check the Dot debug log for Sending CRC. If the Dot does not receive a response or the Conduit
responds with CRC not correct, the Dot discards the file.
Problem: Dot fails to process parity fragments.
Troubleshooting:
If the Conduit sends parity fragments faster than the Dot can process them, the Dot starts failing to
properly receive the fragments. This results in failed MIC checks or wrong address, which is noted in the
Dot debug log.
To correct this, increase the delay between parity fragments on the Conduit.
Problem: Dot is unexpected state.
Troubleshooting:
If the Dot is in a bad or unknown state, use ATZ to reset the Dot and clear the multicast and FOTA
states. AT+FOTA=2 also resets FOTA and Multicast states.
Troubleshooting FOTA on the Conduit
Problem: FOTA Session not starting.
Troubleshooting:
Verify that there is not a current FOTA session. If there is no current FOTA session and a FOTA session
will not start, reboot the Conduit.
If the Conduit does not receive at least one response from an Dot, the FOTA session will not start. The
process will go from SETUP (10%) to TEARDOWN (90%). Check the log (/var/log/log_fota*) to make sure
the Conduit is receiving the setup answers.
Problem: FOTA Session not successful.
Troubleshooting:
For a FOTA Session to be successful, the Dot has to be able to reconstruct the file. If the Dot misses too
many packets, the FOTA session will not be successful and the Dot will not send a CRC to the Conduit.
If the Conduit receives a CRC from an Dot check the FOTA log (/var/log/log_fota*) to make sure the CRC
matches the Conduit and the CRC correct answer is sent back to the Dot. Check the Dot debug log to
verify if the device received the CRC answer.
Problem: Stop FOTA Session / FOTA Session won't start (FOTA in progress) / Stop Multicast Session
Troubleshooting:
To end a FOTA session that is in progress, send 'ps -A | grep fota'. Find the PID associated with lora-fota
(not lora-fota-demo). Then send 'kill (pid of lora-fota)'.
Also send 'rm -r -f ~/.fota/'. Devices may be in Class C or Class A depending on the FOTA session status
before it ended. Make sure to change the devices back to their appropriate class. Make sure the FOTA
daemon is running by '/etc/init.d/fotad restart'.
18
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xDot Developer Guide for Japan