Delete sms on Verizon cause EM7455 to stall or reboot


I have a problem with EM7455 when using a Verizon sim.

When I send a sms delete command (mbim_cid_sms_delete) to the EM7455 module it either stalls (until I power cycle it) or it simply reboot by itself.

The EM7455 is running the latest firmware SWI9X30C_02.33.03.00/002.079_001, and I see the same behavior on older firmware.

I have tried the sms delete command on a many other sim card/mobile network and there it works without any problems.

Sending and receiving sms’s works fine.

Any suggestion?

Hi @mll

Can you please give a try with skylight tool provided by Sierra Wireless?
Step to delete SMS by skylight tool:

  1. Open Skylight tool after installed it (Skylight Windows Connection Manager for EM/MC series modules)
  2. The tool should detect to device automatically. Select SMS express icon on tool UI
  3. SMS express windows should be shown up. You can delete SMS by selected the message on “Inbox” folder, then press delete icon.


Hi Jedung,

Thanks for your response!

The EM7455 module is unfortunately mounted in a embedded device which can’t run Windows programs, so I will not be able to try your suggestion.

I might be able to log info via the DM serial port. (
Do you think this will capture useful information?

Hi @mll

From technical point, user cannot read the log which are captured via DM port, only developer of sierra wireless can.

And if you can only capture the log from DM port. I think it is better to capture DM log then send to the SW developer, please contact to your distributor to get further support.