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Upgrading the JRC MIDlet as part of a FW update | Thales IoT Developer Community

January 16, 2018 - 4:36pm, 3339 views

I'm looking at doing firmware updates in the field and I am trying to figure out a way to update the JRC MIDlet in a fail-safe manor.

My firmware update process goes something like this:

  1. Upload .JAD, .JAR and .USF file to modem's internal FFS using the AT^AT^SJDL=1 command
  2. Verify CRC on each file
  3. Stop currently running MIDlet (JRC MIDlet is the only one installed as I don't have any other applications installed)
  4. Install NEW JRC MIDlet over the top of the old MIDlet
  5. Start NEW JRC MIDlet
  6. Update firmware with AT^SFDL=2 command

If I power cycle during the JRC MIDlet install (step 4), the FFS appears to be inaccessible and AT^SJAM=4 reports nothing installed.

3 Questions:

  1. Am I doing something wrong in my sequence above? 
  2. Is there a way to avoid the state I am currently in and/or make my update recoverable if powercycled at step 4?
  3. Is there a way I can recover this board?