Recover LM940 modules in a WR64/WR54 after a firmware migration

When proceeding with the firmware migration from xOS to DAL on a WR64/WR54, in some rare cases, the cellular modules might not come back after the migration and the router will show no cellular interfaces.

To check if the unit is affected by this problem.

On the web interface of the router, the Status>Modems page will be blank

Via CLI, connect to the admin cli:

The "show usb" command will report:
 

> show usb
 
ID Product Manufacturer
-- ------- ------------

The "show modem" command will report:

> show modem
 

Modem not available.

 
To recover from this state, it is required to issue commands in shell. Please refer to the user guide for details on the allow shell access configuration: https://www.digi.com/resources/documentation/digidocs/90002348/default.htm#os/user-disable-shell-access-t.htm%3FTocPath%3DUser%2520authentication%7C_____8 

Once connected in shell, to recover the modules, issue:

sim1 -o
 
sim2 -o

Wait for a minute or so and issue the following commands to confirm they have an "on" state:

sim1 -p
 
sim2 -p

Then, go back into admin cli and issue a "show usb" . The modules should now be listed:

> show usb
 
 ID         Product   Manufacturer
 
  ---------  --------  ------------------------
  1bc7:1040  LM940-CP  Telit Wireless Solutions
  1bc7:1040  LM940-CP  Telit Wireless Solutions