# MC7455 stops working **URL:** \ **Category:** MC/EM Series\ **Created:** [October 25, 2021, 8:08am UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313 "2021-10-25T08:08:31Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![andreas.lehner](https://avatars.discourse-cdn.com/v4/letter/a/47e85d/32.png) [@andreas.lehner](https://forum.sierrawireless.com/u/andreas.lehner)\ **Post date:** [October 25, 2021, 8:08am UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/1 "2021-10-25T08:08:31Z")
We have problems with several MC7455 modules on a Windows 7 embedded system. Some of the modules stop working after days or weeks of operation. First they disappear from the device manager. And later some even prevent the systems from rebooting as BIOS issues beep code 3 long 2 short. On one of the still operational systems the at!gcdump output showed the following error: Src: FatalError File: lte\_ml1\_schdlr2\_stm.c Line: 1265 Str: Assertion 0 failed 00000000 00000000 00000000 00000000 Prc: MPSS Task: ML1 Time: 0C813D32 R0: EC902000 R1: DE5C2D38 R2: 58D0A334 R3: 00F5A2F1 R4: 000058D0 R5: 00000000 R6: 000000A2 R7: 00000000 R8: 00F5A2F1 R9: 00000000 R10: 000000F5 R11: 7EC171CD R12: 000000F5 R13: 00000000 R14: 00000000 R15: 00000000 R16: 055607E0 R17: 00000000 R18: 00000000 R19: 0384DF30 R20: 000000C4 R21: 000000FD R22: 018E97CC R23: 00000000 R24: 00000001 R25: 018E8E08 R26: 00000001 R27: 00000000 R28: 00000000 SP: 1E9DEA78 FP: 1E9DEA80 LR: 02129158 PC: 01BD1E6C CPSR: 00000000 Mod: Unknown TOS 1E9DEA98 02129198 00003D5F 0384DF30 0384DF28 00000000 1E9DEBF8 01BD1E6C 000000C4 00001560 0000155F 00003D5F 9135F8AC 000005DC 9135F84E 000005DC FFFFFFFF 00000000 00000030 00000739 00000030 00000739 00001560 00001560 00000000 00000000 9135F8AC 000005DC 9135F84E 000005DC FFFFFFFF 00000000 BOS App ver: SWI9X30C\_02.24.05.06 OK Are we facing hardware failures? Or can it be resolved with e.g. SW update? We are using “GenericDriverSetup\_5087” and have set the interface to at!usbcomp=1,1,50d. The voltage quere at!pcvolt? gives 3316mV. Please can you give advice of how to resolve the failures? ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 25, 2021, 9:12am UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/2 "2021-10-25T09:12:54Z")
have you tried the latest FW? ---
**Author:** ![andreas.lehner](https://avatars.discourse-cdn.com/v4/letter/a/47e85d/32.png) [@andreas.lehner](https://forum.sierrawireless.com/u/andreas.lehner)\ **Post date:** [October 28, 2021, 2:56pm UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/3 "2021-10-28T14:56:16Z")
I just tried the latest FW 02.33.03.00. Now I can’t connect to the carrier anymore. Even if I go back to the older FW. Somehow the device seems broken. HW failure? ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 28, 2021, 3:18pm UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/4 "2021-10-28T15:18:13Z")
What is at!gstatus? returned ---
**Author:** ![andreas.lehner](https://avatars.discourse-cdn.com/v4/letter/a/47e85d/32.png) [@andreas.lehner](https://forum.sierrawireless.com/u/andreas.lehner)\ **Post date:** [October 28, 2021, 5:39pm UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/5 "2021-10-28T17:39:59Z")
at!gstatus? !GSTATUS: Current Time: 21 Temperature: 39 Reset Counter: 3 Mode: ONLINE System mode: WCDMA PS state: Not attached WCDMA band: WCDMA 2100 WCDMA channel: 10674 GMM (PS) state:DEREGISTERED PLMN SEARCH MM (CS) state: IDLE PLMN SEARCH WCDMA L1 state:L1M\_ACQ LAC: 0000 (0) RRC state: DISCONNECTED Cell ID: 00000000 (0) RxM RSSI C0: — RxD RSSI C0: — RxM RSSI C1: — RxD RSSI C1: — OK But all is fine if I replace the module. Thus, system, drivers, antenna, SIM must be ok. ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 29, 2021, 1:17am UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/6 "2021-10-29T01:17:00Z")
how about using AT!RMARESET ---
**Author:** ![andreas.lehner](https://avatars.discourse-cdn.com/v4/letter/a/47e85d/32.png) [@andreas.lehner](https://forum.sierrawireless.com/u/andreas.lehner)\ **Post date:** [October 29, 2021, 5:54am UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/7 "2021-10-29T05:54:19Z")
at!rmareset ERROR AT!RMARESET=1 !RMARESET: DEVICE REBOOT REQUIRED Items Restored: 0 Items Deleted: 0 ERROR at!image? TYPE SLOT STATUS LRU FAILURES UNIQUE\_ID BUILD\_ID FW 1 GOOD 6 0 0 ?_? 02.24.05.06_? FW 2 GOOD 4 0 0 ?_? 02.33.03.00_? FW 3 GOOD 5 0 0 ?_? 02.20.03.00_? 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 0 002.026\_000 02.24.05.06\_GENERIC Max PRI images: 50 ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 29, 2021, 6:36am UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/8 "2021-10-29T06:36:15Z")
how about AT!entercnd=“A710” AT!impref? AT!PCINFO? At!band? At!selrat? At+cgdcont? ---
**Author:** ![andreas.lehner](https://avatars.discourse-cdn.com/v4/letter/a/47e85d/32.png) [@andreas.lehner](https://forum.sierrawireless.com/u/andreas.lehner)\ **Post date:** [October 29, 2021, 7:58am UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/9 "2021-10-29T07:58:32Z")
at!entercnd=“A710” OK AT!impref? !IMPREF: preferred fw version: 02.33.03.00 preferred carrier name: GENERIC preferred config name: GENERIC\_002.072\_000 preferred subpri index: 000 current fw version: 02.33.03.00 current carrier name: GENERIC current config name: GENERIC\_002.072\_000 current subpri index: 000 OK AT!PCINFO? State: Online LPM voters - Temp:0, Volt:0, User:0, W\_DISABLE:0, IMSWITCH:0, BIOS:0, LWM2M:0, OMADM:0, FOTA:0 LPM persistence - None OK At!band? Index, Name, GW Band Mask L Band Mask TDS Band Mask 00, All bands, 0002000007C00000 00000100330818DF 0000000000000000 OK At!selrat? !SELRAT: 00, Automatic OK At+cgdcont? +CGDCONT: 1,“IPV4V6”,“internet.t-mobile”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,0 OK ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 29, 2021, 8:00am UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/10 "2021-10-29T08:00:17Z")
Is the SIM card OK? you can also check if AT+COPS=? can scan some network operator Also what is the return of these? AT!UIMS? AT+CPIN? ---
**Author:** ![andreas.lehner](https://avatars.discourse-cdn.com/v4/letter/a/47e85d/32.png) [@andreas.lehner](https://forum.sierrawireless.com/u/andreas.lehner)\ **Post date:** [October 29, 2021, 8:17am UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/11 "2021-10-29T08:17:55Z")
SIM should be ok. Everything works if I repace the module. at+cops? +COPS: 0 OK AT!UIMS? !UIMS: 0 OK AT+CPIN? +CPIN: READY OK ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 29, 2021, 8:33am UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/12 "2021-10-29T08:33:22Z")
are you using GENERIC FW before? ---
**Author:** ![andreas.lehner](https://avatars.discourse-cdn.com/v4/letter/a/47e85d/32.png) [@andreas.lehner](https://forum.sierrawireless.com/u/andreas.lehner)\ **Post date:** [October 29, 2021, 11:48am UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/13 "2021-10-29T11:48:42Z")
Yes, the modul came with SWI9X30C\_02.24.05.06\_00\_GENERIC\_002.026 firmware and I updated to SWI9X30C\_02.33.03.00\_00\_GENERIC\_002.072 as recommend by you. In fact, the update worked on another device without problem. But this other device had an empty crash dump log. ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 29, 2021, 2:09pm UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/14 "2021-10-29T14:09:15Z")
No idea if it only happens to particular module ---
**Author:** ![andreas.lehner](https://avatars.discourse-cdn.com/v4/letter/a/47e85d/32.png) [@andreas.lehner](https://forum.sierrawireless.com/u/andreas.lehner)\ **Post date:** [October 29, 2021, 3:07pm UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/15 "2021-10-29T15:07:20Z")
Great, now I have a damaged device? How to return it? What about Sierra customer support? ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 29, 2021, 3:55pm UTC](https://forum.sierrawireless.com/t/mc7455-stops-working/25313/16 "2021-10-29T15:55:56Z")
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