AC1300 Cirrus Router - IMEI Change AT Command

I tried running the AT command to change my IMEI on the AT1300 Cirrus router, however, now I only see the IMEI appearing as an empty - rather than the IMEI I entered. The command seems to be accepted but does not appear to be working.



Is this command still correct for this router?

What is the modem? EC25?
Could you give screenshot of the AT command input and return?