EM7455B getting No Service. Windows 11 FZ-G1

IoT Modules MC/EM Series
1

I am having trouble with this LTE module across multiple FZ-G1 devices and Verizon service. Most of them I have resolved connectivity issues by updating to the latest drivers and then flashing to the latest Verizon firmware - 2.33.03.00_VERIZON

One particular FZ-G1 is giving me persistent issues. When I run the firmware update tool, I get some errors as you can see in the screenshot I have attached. However the firmware update did seem to work initially and I do get service, however after a few days of usage it falls back into No Service mode. Running the firmware update tool again seems to wake the card up and resume service, however after some time it falls back into No Service again.

Please let me know if there are any AT commands I can run to troubleshoot this issue, thank you!

Screenshot 2025-08-27 152942
Screenshot 2025-08-27 1529421076×624 105 KB

2

I have some experience with this module. Reads like two problems. When the module is in no service, what is the response to AT!GSTATUS? would like to see the response to understand LTE communications with the LTE network.

What is the response to AT!IMPREF? and AT!IMAGE? would love to see what is the IMage PREFerence and what IMAGES are loaded.

There is another command I would like to see but have to check the AT command guide. I will check and reply soon.

3

What is the return of the following AT commands?

at!entercnd="A710"
at!bsinfo
ati3
AT!IMPREF?
at!gstatus?
AT+Cpin?
AT!UIMS?
AT!band?
AT!selrat?
at!image?
4

Thanks for getting back to me! After I ran the firmware updater yesterday to get the screenshot, the device is still properly receiving service. I’m not sure what triggers the No Service - these tablets are provided to service technicians for use in the field and I only get a call once it hasnt been working for a bit. I am keeping this one at my desk over the next few days to see when/if it falls back into No Service mode.

I ran the commands you provided and here are the results-

at!entercnd=“A710”

Recieve: AT!entercnd=“A710”
Recieve: OK

Send:AT!bsinfo

Recieve: AT!bsinfo
Recieve: Product: EM7455B
Recieve: Revision: 40
Recieve: Main: MDM9230 (002)
Recieve: Radio: WTR3925
Recieve: Power: PMD9635 (001)
Recieve: Flash: MT29F4G08ABBFA3W 512MB x8 (44/0/0) (2048 blocks of 64 pages/block 4096B page size)
Recieve: OK

Send:ati3

Recieve: ati3
Recieve: Manufacturer: Sierra Wireless, Incorporated
Recieve: Model: EM7455B
Recieve: Revision: SWI9X30C_02.33.03.00 r8209 CARMD-EV-FRMWR2 2019/08/28 20:59:30
Recieve: MEID: A10000747A77B3
Recieve: ESN: 12802473253, 8025BD25
Recieve: IMEI: 990008248678968
Recieve: IMEI SV: 20
Recieve: FSN: LF221352440110
Recieve: +GCAP: +CGSM
Recieve: OK

Send:AT!IMPREF?

Recieve: AT!IMPREF?
Recieve: !IMPREF:
Recieve: preferred fw version: 02.33.03.00
Recieve: preferred carrier name: VERIZON
Recieve: preferred config name: VERIZON_002.079_002
Recieve: preferred subpri index: 000
Recieve: current fw version: 02.33.03.00
Recieve: current carrier name: VERIZON
Recieve: current config name: VERIZON_002.079_002
Recieve: current subpri index: 000
Recieve: OK

Send:AT!gstatus?

Recieve: AT!gstatus?
Recieve: !GSTATUS:
Recieve: Current Time: 416 Temperature: 40
Recieve: Reset Counter: 1 Mode: ONLINE
Recieve: System mode: LTE PS state: Attached
Recieve: LTE band: B4 LTE bw: 20 MHz
Recieve: LTE Rx chan: 2050 LTE Tx chan: 19075
Recieve: LTE CA state: NOT ASSIGNED
Recieve: EMM state: Registered Normal Service
Recieve: RRC state: RRC Idle
Recieve: IMS reg state: Full Srv IMS mode: Normal
Recieve: PCC RxM RSSI: -57 RSRP (dBm): -84
Recieve: PCC RxD RSSI: -62 RSRP (dBm): -89
Recieve: Tx Power: – TAC: 4005 (16389)
Recieve: RSRQ (dB): -7.3 Cell ID: 00FC7416 (16544790)
Recieve: SINR (dB): 25.8
Recieve: OK

Send:AT+Cpin?

Recieve: AT+Cpin?
Recieve: +CPIN: READY
Recieve: OK

Send:AT!UIMS?

Recieve: AT!UIMS?
Recieve: !UIMS: 0
Recieve: OK

Send:AT!band?

Recieve: AT!band?
Recieve: Index, Name, GW Band Mask L Band Mask TDS Band Mask
Recieve: 00, All bands, 0002000007C00000 000000000000101A 0000000000000000
Recieve: OK

Send:AT!selrat?

Recieve: AT!selrat?
Recieve: !SELRAT: 00, Automatic
Recieve: OK

Send:AT!image?

Recieve: AT!image?
Recieve: TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
Recieve: FW 1 GOOD 1 0 0 ?? 02.20.03.00?
Recieve: FW 2 GOOD 2 0 0 ?? 02.33.03.00?
Recieve: FW 3 EMPTY 0 0 0
Recieve: FW 4 EMPTY 0 0 0
Recieve: Max FW images: 4
Recieve: Active FW image is at slot 2
Recieve: TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
Recieve: PRI FF GOOD 0 0 0 002.017_002 02.20.03.00_GENERIC
Recieve: PRI FF GOOD 0 0 0 002.079_002 02.33.03.00_VERIZON
Recieve: Max PRI images: 50
Recieve: OK

5

everything seems to be fine in the AT command response

6

Thank you, I will re-run these commands when/if it falls back into No Service mode. It has consistently been reverting to No Service within a few days of running the firmware update to ‘wake it up’.

7

please also add “AT+CGDCONT?” to make sure it is using correct APN.

8

I reviewed those AT command responses. I agree with jyijyi, they look good! I see from the AT!GSTATUS? response, you are on LTE Band 4. That is a Verizon LTE band. Also, I see the IMS reg state is Full and IMS mode is normal. This is great and normal.

What you said about the field technicians is a great clue.

What could be happening is - they are in low or poor coverage and the module goes to another LTE network or non LTE network and gets “stuck” there for some reason. I am not sure. This is a theory.

What you could do is - lock the module to LTE only with the AT!SELRAT=6 command. This command will keep it on LTE, prevent it from going to the other wireless networks that the module supports. Meaning UMTS. Once you set AT!SELRAT=6, it stays set this way until you change it back to AT!SELRAT=00, the default.

When the field technician is in a no service state, Verizon Support could help with more information about the condition. Note the MDN or phone number, the day and time. If you get this to Verizon Support in 1-2 days, they can see the network information.

9

After staying powered off through the night, I booted the FZ-G1 up today and the LTE was in No Service mode. I re-ran the commands and here are the results. I can see the card is now reporting Low Power Mode and the AT!IMPREF? command produced different results. Appreciate any advice on this.

Send:AT!entercnd=“A710”

Recieve: AT!entercnd=“A710”
Recieve: OK

Send:AT!bsinfo

Recieve: AT!bsinfo
Recieve: Product: EM7455B
Recieve: Revision: 40
Recieve: Main: MDM9230 (002)
Recieve: Radio: WTR3925
Recieve: Power: PMD9635 (001)
Recieve: Flash: MT29F4G08ABBFA3W 512MB x8 (44/0/0) (2048 blocks of 64 pages/block 4096B page size)
Recieve: OK

Send:ati3

Recieve: ati3
Recieve: Manufacturer: Sierra Wireless, Incorporated
Recieve: Model: EM7455B
Recieve: Revision: SWI9X30C_02.33.03.00 r8209 CARMD-EV-FRMWR2 2019/08/28 20:59:30
Recieve: MEID: A10000747A77B3
Recieve: ESN: 12802473253, 8025BD25
Recieve: IMEI: 990008248678968
Recieve: IMEI SV: 20
Recieve: FSN: LF221352440110
Recieve: +GCAP: +CGSM
Recieve: OK

Recieve: AT!IMPREF?
Recieve: !IMPREF:
Recieve: preferred fw version: 02.30.01.01
Recieve: preferred carrier name: VERIZON
Recieve: preferred config name: VERIZON_002.052_002
Recieve: preferred subpri index: 000
Recieve: current fw version: 02.33.03.00
Recieve: current carrier name: VERIZON
Recieve: current config name: VERIZON_002.079_002
Recieve: current subpri index: 000
Recieve: fw version mismatch
Recieve: config name mismatch
Recieve: OK

Send:AT!gstatus?

Recieve: AT!gstatus?
Recieve: !GSTATUS:
Recieve: Current Time: 326 Temperature: 41
Recieve: Reset Counter: 2 Mode: LOW POWER MODE
Recieve: OK

Send:AT+cpin?

Recieve: AT+cpin?
Recieve: +CPIN: READY
Recieve: OK

Send:AT!UIMS?

Recieve: AT!UIMS?
Recieve: !UIMS: 0
Recieve: OK

Send:AT!band?

Recieve: AT!band?
Recieve: Index, Name, GW Band Mask L Band Mask TDS Band Mask
Recieve: 00, All bands, 0002000007C00000 000000000000101A 0000000000000000
Recieve: OK

Send:AT!selrat?

Recieve: AT!selrat?
Recieve: !SELRAT: 00, Automatic
Recieve: OK

Send:AT!image?

Recieve: AT!image?
Recieve: TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
Recieve: FW 1 GOOD 1 0 0 ?? 02.20.03.00?
Recieve: FW 2 GOOD 2 0 0 ?? 02.33.03.00?
Recieve: FW 3 EMPTY 0 0 0
Recieve: FW 4 EMPTY 0 0 0
Recieve: Max FW images: 4
Recieve: Active FW image is at slot 255
Recieve: TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
Recieve: PRI FF GOOD 0 0 0 002.017_002 02.20.03.00_GENERIC
Recieve: PRI FF GOOD 0 0 0 002.079_002 02.33.03.00_VERIZON
Recieve: Max PRI images: 50
Recieve: OK

Send:AT+CGDCONT?

Recieve: AT+CGDCONT?
Recieve: +CGDCONT: 1,“IPV4V6”,“ims”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,0
Recieve: +CGDCONT: 2,“IPV4V6”,“vzwadmin”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,0
Recieve: +CGDCONT: 3,“IPV4V6”,“vzwinternet”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,0
Recieve: +CGDCONT: 4,“IPV4V6”,“vzwapp”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,0
Recieve: +CGDCONT: 5,“IPV4V6”,“vzw800”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,0
Recieve: +CGDCONT: 6,“IPV4V6”,“vzwclass6”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,0
Recieve: OK

10

Thanks for responding, this does make a lot of sense with the field technicians going into a bad service area. However, I experienced this same issue today at my desk where the device has not moved.

11

What is the return of "at!pcinfo? " now?
It might tell why module stuck in low power mode

12

Send:AT!PCINFO?

Recieve: AT!PCINFO?
Recieve: State: Low Power Mode
Recieve: LPM voters - Temp:0, Volt:0, User:0, W_DISABLE:0, IMSWITCH:1, BIOS:0, LWM2M:0, OMADM:0, FOTA:0
Recieve: LPM persistence - None
Recieve: OK

13

here shows why the module is kept in low power mode:

Recieve: AT!IMPREF?
Recieve: !IMPREF:
Recieve: preferred fw version: 02.30.01.01
Recieve: preferred carrier name: VERIZON
Recieve: preferred config name: VERIZON_002.052_002
Recieve: preferred subpri index: 000
Recieve: current fw version: 02.33.03.00
Recieve: current carrier name: VERIZON
Recieve: current config name: VERIZON_002.079_002
Recieve: current subpri index: 000
Recieve: fw version mismatch
Recieve: config name mismatch
Recieve: OK

But I don’t know why it needs the firmware that is not inside AT!IMAGE.
Maybe your PC has downloaded some wrong files to it.

Now you can try to use the following and see if it can be recovered:

AT!IMAGE="GENERIC"
AT!RESET
AT!IMAGE="VERIZON"
AT!RESET
14

I get errors when I try to run that command -

Send:AT!IMAGE=“GENERIC”

Recieve: AT!IMAGE=“GENERIC”
Recieve: ERROR

Send:AT!IMAGE=“VERIZON”

Recieve: AT!IMAGE=“VERIZON”
Recieve: ERROR

Regarding the file downloads - I have only used the latest driver + firmware file from source.sierrawireless.com/resources/airprime/minicard/74xx/em_mc74xx-approved-fw-packages/

15

Maybe you need to unlock the module by at!entercnd=“A710” first

16

I have been following this. I agree with jyijyi. I think there are files on the laptop/Windows that are causing the IMAGE switch. Causing this problem. Odd though. Maybe get the driver package that does not have the FW images as part of it. Just the drivers. That would be what I would suggest.

jyijyi, where does he get these? from his distributor or FAE?

18

I don’t know, maybe he changes the module of the pc by himself

I am also thinking switching between rmnet and mbim mode by at!usbcomp command can overcome this problem

19

Based on your post I did some digging for updated drivers and discovered -

Cellular (WWAN) Drivers | Panasonic North America - United States

as well as the direct link to 7455 module -

Download

Compared to build 5087 on the sierra website, this one is on Build 5243

source.sierrawireless.com/resources/airprime/software/airprime-em_mc-series-windows-drivers-qmi-build-latest-release/

I was using 5087 along with the latest firmware from my other post link, perhaps some incompatibility between them was causing the low power mode.

I installed the updated drivers 5243 and have service on reboot. I will monitor over the next few days to see if the device falls back into low power mode.

Thanks to both of you for your efforts in helping me resolve this, I appreciate it.

20

I understand your response. Yes, that could be something or the source of the problem.

I have a new question for jyijyi, there is a location on the Windows hard drive where the FW images are stored, right?

Maybe we should check the images in that location?

21

I am wondering if the skylight will store some image in the PC…