MC7304 and Roaming

I’m trying to disable roaming on a MC7304 card using AT commands, that I found in the document “2130617_standard_at_commands_v7”, downloaded from the resource section of the card.
As suggested in this web page,, I used
AT^SYSCONFIG=16,3,1,4, to permit roaming
AT^SYSCONFIG=16,3,0,4, to disable roaming
The commands seem to work, as you can see in this sequence:

^SYSCONFIG: 2,0,1,1 (roaming enabled)

AT^SYSCONFIG=16,3,0,4 (disable roaming)

^SYSCONFIG: 2,0,0,1 (roaming disabled)

AT^SYSCONFIG=16,3,1,4 (enable roaming)

^SYSCONFIG: 2,0,1,1 (roaming enabled)

I tried to disable roaming when I was abroad, to be sure not to be able to connect to my home network with my sim, but the command AT^SYSCONFIG=16,3,0,4 did’nt work; in fact the MC7304 registred itself to the network, as you can see from the result of the command SYSINFO:
^SYSINFO: 2,3,1,9,1
^SYSCONFIG: 2,0,0,1

I know I can handle roaming by software, using MCC and MNC of the sim operator and the current operator registred on the network, but the card MC7304 is installed on a routerboard Mikrotik, and I have only one channel (number 2) for data and info; to check the status of card, and so get the code of the current operator, I need to disable the card, terminating the connection.
Consequently I can only check the status of roaming at startup, not at run-time.

The firmware version the the card is:
SWI9X15C_05.05.66.00 r29972 CARMD-EV-FRMWR1 2015/10/08 08:36:28

Please, help me.

As a workaround, i will use the command AT+COPS to disable roaming.
It will force the home network:
where nnnnn is the home network code, MCC + MNc
Let me know if you have a better idea, or you know a firmware version for the MC7304 that supports enabling/disabling roaming.