BG95-M4 bricked after DFOTA

vermutlich · February 19, 2026, 1:29am

Hello everyone,

I am using a BG95-M4 modem on the UMTS & LTE EVB Kit. After a supposedly successful firmware update (DFOTA) from BG95M4LAR02A02_01.005.01.005 to BG95M4LAR02A02_A0.206.A0.206, the module no longer starts when PWRKEY is pressed. The status LED flashes slowly and no COM ports are recognized by the computer.

I have already found out that when USB_BOOT and VDD_EXT are connected via a 4.7kOhm resistor, the Quectel QLoader 9008 port opens. All attempts to update or recover firmware version A0.206 via thisport and using QFlash_V4.18 were unsuccessful. QFlash confirms successful upgrade of the module, but the modem still does not start up with the error described.

Am I doing something wrong? Can someone show me how to get the modem working properly again? Or is it beyond repair?

Best regards

Linkin-Q · February 25, 2026, 9:09am

HI @vermutlich

Is possible to using latest QFLASH tool to try again? we have never received similar issue.

you can download here: https://www.quectel.com/download-zone/?_sf_s=QFLASH

vermutlich · February 25, 2026, 10:55am

Hello @Linkin-Q,

Thanks for the advice. I repeated the update process with the current version of QFlash (with and without the “Sahara only” option). The update appears to have been successful, but unfortunately the modem still isn’t working. It’s behaving as described above.

Perhaps I have the wrong files for the update/recovery. Can you let me know whether the selected files are suitable? Or should I use the files from the folder BG95M4LAR02A02_A0.206.A0.206\dam\recover\firehose?

Or maybe I’m doing something wrong after the update? After QFlash gives the PASS, I turn off the power on the EVB Kit using the POWER switch. Then I remove the resistor between USB_BOOT and VDD_EXT, switch the kit back on, press PWRKEY and watch the COM ports open (still none detected). Can you comment on this?

Thank you in advance for your help.

Best regards

vermutlich · February 25, 2026, 12:29pm

I have made some progress: I was able to update the modem using the old firmware version BG95M4LAR02A02_01.005.01.005 files (without the “Sahara only” option). Apparently, the files I have of firmware version BG95M4LAR02A02_A0.206.A0.206 are faulty or incompatible.

The modem is now working again, but with the old firmware version. @Linkin-Q, could you please send me the files of the latest firmware version for BG95-M4 so that I can successfully update the modem?

Best regards

Linkin-Q · March 6, 2026, 5:46am

Hi @vermutlich

You can find latest FW

vermutlich · March 6, 2026, 7:18am

Hello @Linkin-Q,

Thank you very much for providing latest firmware files. I will try to update the EVB Kit with them and let you know if it worked.

Best regards

vermutlich · March 11, 2026, 12:09pm

Hello @Linkin-Q,

Unfortunately, the modem update did not work with the new firmware BG95M4LAR02A02_A0.301.A0.301 either.

As with firmware BG95M4LAR02A02_A0.206.A0.206, the update with QFlash_V7.7 was unsuccessful. After the update, the modem still does not show any COM ports and the STATUS LED flashes slowly and eventually dies.

After this failure, I was able to recover the modem to the old status BG95M4LAR02A02_01.005.01.005 using the familiar method via the Quectel QLoader 9008 port. So the current status is the same as at the beginning. But how can I successfully update the firmware? Maybe it will work with DFOTA?

@Linkin-Q, could you please send me a DFOTA update file from firmware version BG95M4LAR02A02_01.005.01.005 to BG95M4LAR02A02_A0.301.A0.301 so I can try it out?
And while you’re at it, I have another BG95-M4 installed in a prototype PCB here with firmware version BG95M4LAR02A02_A0.206.A0.206. Could you also provide me with a DFOTA update file for updating it to BG95M4LAR02A02_A0.301.A0.301?

Best regards

vermutlich · April 14, 2026, 9:35am

Hi @Linkin-Q,

I received the DFOTA image for version BG95M4LAR02A02_A0.301.A0.301 from our modem distributor. Unfortunately, this update didn’t work either.

Here is a log of the serial interface during the update process:

2026-04-13 12:23:01:286[Send->]AT+QFOTADL="http://xxx.xxx.xxx.xxx/BG95M4LAR02A02_01.005.A0.301.bin"

2026-04-13 12:23:01:286[Recv<-]AT+QFOTADL="http://xxx.xxx.xxx.xxx/BG95M4LAR02A02_01.005.A0.301.bin"
OK

2026-04-13 12:23:01:357[Recv<-]
+QIND: "FOTA","HTTPSTART"

2026-04-13 12:37:13:342[Recv<-]
+QIND: "FOTA","DOWNLOADING",5%

2026-04-13 12:51:52:208[Recv<-]
+QIND: "FOTA","DOWNLOADING",10%

2026-04-13 13:06:16:792[Recv<-]
+QIND: "FOTA","DOWNLOADING",15%

2026-04-13 13:21:06:163[Recv<-]
+QIND: "FOTA","DOWNLOADING",20%

2026-04-13 13:35:08:462[Recv<-]
+QIND: "FOTA","DOWNLOADING",25%

2026-04-13 13:49:36:734[Recv<-]
+QIND: "FOTA","DOWNLOADING",30%

2026-04-13 14:04:05:884[Recv<-]
+QIND: "FOTA","DOWNLOADING",35%

2026-04-13 14:18:37:745[Recv<-]
+QIND: "FOTA","DOWNLOADING",40%

2026-04-13 14:33:00:694[Recv<-]
+QIND: "FOTA","DOWNLOADING",45%

2026-04-13 14:47:07:772[Recv<-]
+QIND: "FOTA","DOWNLOADING",50%

2026-04-13 15:01:28:797[Recv<-]
+QIND: "FOTA","DOWNLOADING",55%

2026-04-13 15:16:04:591[Recv<-]
+QIND: "FOTA","DOWNLOADING",60%

2026-04-13 15:30:41:505[Recv<-]
+QIND: "FOTA","DOWNLOADING",65%

2026-04-13 15:45:16:040[Recv<-]
+QIND: "FOTA","DOWNLOADING",70%

2026-04-13 15:59:24:282[Recv<-]
+QIND: "FOTA","DOWNLOADING",75%

2026-04-13 16:14:06:381[Recv<-]
+QIND: "FOTA","DOWNLOADING",80%

2026-04-13 16:28:44:030[Recv<-]
+QIND: "FOTA","DOWNLOADING",85%

2026-04-13 16:43:22:081[Recv<-]
+QIND: "FOTA","DOWNLOADING",90%

2026-04-13 16:57:47:859[Recv<-]
+QIND: "FOTA","DOWNLOADING",95%

2026-04-13 17:12:34:418[Recv<-]
+QIND: "FOTA","DOWNLOADING",100%

2026-04-13 17:12:42:254[Recv<-]
+QIND: "FOTA","HTTPEND",0

+QIND: "FOTA","RESETTING"

2026-04-13 17:12:42:318[Send->]Port Control Line: CI (CT125) is [1]!

+QIURC: "pdpdeact",1

2026-04-13 17:12:42:446[Send->]Port Control Line: CI (CT125) is [0]!

2026-04-14 09:33:55:967[Send->]AT

2026-04-14 09:34:07:746[Send->]AT

2026-04-14 09:34:11:571[Send->]AT+CPIN?

Nothing happened after these last lines of the reset process. For many hours, the modem is unreachable and no COM ports are available. The symptoms after the failed update are the same as I described in the first post in this thread.

It almost seems as if there is no way to update the modem to a firmware version other than BG95M4LAR02A02_01.005.01.005. Can you please help me with the update? I need access to the new features in the newer firmware versions on the EVB Kit.

Best regards