Mc7455 auto-sim issue

IoT Modules MC/EM Series
1

I have a MC7455 with AUTO-SIM feature not working. Check the modem with the AT!IMPREF? and found that it only had one Firmware and Carrier PRI Cached on it (as shown below)
AT!IMAGE?
TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
FW 1 GOOD 1 0 0 ?? 02.33.03.00?
FW 2 EMPTY 0 0 0
FW 3 EMPTY 0 0 0
FW 4 EMPTY 0 0 0
Max FW images: 4
Active FW image is at slot 1

TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
PRI FF GOOD 0 0 0 002.072_000 02.33.03.00_GENERIC
Max PRI images: 50

I suspected that, this is the reason for the auto sim feature not working and loaded AT&T and Verizon Firmware using the firmware executable files downloaded from Sierra wireless website.

AT!IMAGE?
TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
FW 1 GOOD 3 0 0 ?? 02.33.03.00?
FW 2 GOOD 2 0 0 ?? 02.32.11.00?
FW 3 EMPTY 0 0 0
FW 4 EMPTY 0 0 0
Max FW images: 4
Active FW image is at slot 1

TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
PRI FF GOOD 0 0 0 002.070_005 02.32.11.00_ATT
PRI FF GOOD 0 0 0 002.072_000 02.33.03.00_GENERIC
PRI FF GOOD 0 0 0 002.079_002 02.33.03.00_VERIZON
Max PRI images: 50

OK
I set the firmware using the AT!IMPREF=“ATT” to set the carrier to AT&T
Then set AUTO-SIM feature as below:
AT!IMPREF=“AUTO-SIM”
OK
AT!RESET
OK
When a Verizon SIM is used the firmware remained to generic rather than switching to Verizon SIM.
Anyone has a solution to this?

2

Do these help?

3

Thanks for the information. The manual firmware switching using the AT command (AT!IMPREF=“FIRMWARE”) works. However, the auto firmware switching does not work.
As the AUTO-SIM is the preference, is there any way we can add the MCC/MNC pair combinations to the modem?
Is manually switching the firmware using the AT command the only way if the MCC/MNC combination is not identified ?

4

if the MCC/MNC combination is not identified, you can use the SDK or AT command to switch PRI

5

Hi @jyijyi,

can you please provide some information on the following:

  1. From the link of the topic your shared, it says that auto SIM switching works when it is faced with known MCC/MNC. Is there any way we can manually update this known MCC/MNC combination on the modem?

thanks,

6

no, i don’t see there is any way to do this manually

You might need to monitor the ICCID and MCC/MNC on host side

7

Hi Jyijyi,

Thanks for the information on manual update of MCC/MNC.

Just wondering whether the EOL of MC7455 has an impact on the AUTO-SIM functionality?

8

For EOL, probably there will not be any update of FW

9

Hi Jyijyi,

Thanks for the following information that you have provided me through our conversation, correct me if i am wrong:

  1. the issue that i am facing is due to my SIM’s MCC/MNC combination being new and not available in the carrier firmware images. This means the auto SIM will not work with this SIM unless there is a new firmware release. which won’t happen as MC7455 is EOL.
  2. the only way around this issue is to manually switching the firmware using the AT command.

Can you please confirm that the above two points are correct.

10

yes. i think you need to manually switching the IMPREF

11

Thanks for confirming this and helping me out out on the issue.