I'm unable to upload more than 3KB of data into the RAM of the Quectel EC25 modem using the AT+QFUPL command. The modem consistently fails to handle larger files?

Pankaj_prasad1 · April 24, 2025, 1:43pm

Hello,

I’m working with the Quectel EC25 module, and I’m currently trying to store data into the module’s RAM using the AT+QFUPL command.

The issue I’m facing is that the upload fails consistently if the data size exceeds ~3KB. Uploads of smaller files (under 3KB) work fine. However, anything beyond that either hangs or returns an error like CME ERROR: 421.

Here’s a snippet from my log:

AT

OK

+CFUN: 1

Command : AT+CFUN=?
Responce: AT+CFUN=?

+CFUN: (0,1,4),(0,1)

OK

+IFC: 0,0

OK

+QIND: PB DONE

Command : AT+IFC=2,2
Responce: AT+IFC=2,2

OK

Command : ATE0
Responce: ATE0

OK

Command : AT+QURCCFG=“urcport”,“uart1”
Responce:

OK

Command : AT+QCCID
Responce:

+QCCID: 8991000908580317531F

OK

Command : AT+CGMR
Responce:

EC25EFAR06A16M4G

OK

Command : AT+CPIN?
Responce:

+CPIN: READY

OK

Command : AT+QGMR
Responce:

EC25EFAR06A16M4G_20.200.20.200

OK

Command : AT+QFLDS=“RAM”
Responce:

+QFLDS: 2606080,2616320

OK

*Command : AT+QFDEL=“RAM:EVENT3.TXT”
*Responce:

+CME ERROR: 418

Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
Responce:

CONNECT

*Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
*Responce: +QFUPL: 4218,2637

+CME ERROR: 421

Command : AT+QFDEL=“RAM:EVENT3.TXT”
Responce:

OK

Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
Responce:

CONNECT

*Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
*Responce: +QFUPL: 4218,2637

+CME ERROR: 421

Command : AT+QFDEL=“RAM:EVENT3.TXT”
Responce:

OK

Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
Responce:

CONNECT

*Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
*Responce: +QFUPL: 4218,2637

+CME ERROR: 421

herbert.pan-Q · April 25, 2025, 1:11am

psl run

AT+QFLDS
AT+QFLST=“*”

Pankaj_prasad1 · April 25, 2025, 3:39am

Here is the log

Command : AT
Responce: AT

OK

Command : AT+CFUN=?
Responce: AT+CFUN=?

+CFUN: (0,1,4),(0,1)

OK

+IFC: 0,0

OK

Command : AT+IFC=2,2
Responce: AT+IFC=2,2

OK

Command : AT+IFC?
Responce: AT+IFC?

+IFC: 2,2

OK

Command : ATE0
Responce: ATE0

OK

Command : AT+QURCCFG=“urcport”,“uart1”
Responce:

OK

Command : AT+QCCID
Responce:

+QCCID: 8991000908580317531F

OK

Command : AT+CGMR
Responce:

EC25EFAR06A16M4G

OK

Command : AT+CPIN?
Responce:

+CPIN: READY

OK

Command : AT+QGMR
Responce:

EC25EFAR06A16M4G_20.200.20.200

OK

Command : AT+QFLDS=“RAM”
Responce:

+QFLDS: 2606080,2616320

OK

Command : AT+QFLDS
Responce:

+QFLDS: 4159,1

OK

Command : AT+QFLST=“*”
Responce:

+QFLST: “UFS:EVENT3.TXT”,4159

OK

*Command : AT+QFDEL=“RAM:EVENT3.TXT”
*Responce:

+CME ERROR: 418

Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
Responce:

CONNECT

*Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
*Responce: +QFUPL: 4218,2637

+CME ERROR: 421

Command : AT+QFDEL=“RAM:EVENT3.TXT”
Responce:

OK

Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
Responce:

CONNECT

*Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
*Responce: +QFUPL: 4218,2637

+CME ERROR: 421

herbert.pan-Q · April 25, 2025, 5:23am

This file already exists. You need to delete it and then re-import it

Pankaj_prasad1 · April 25, 2025, 6:10am

Here you can see i deleted the file but still not able to upload.

Command : AT
Responce:

OK

Command : AT+CFUN=?
Responce:

+CFUN: (0,1,4),(0,1)

OK

Command : AT+IFC?
Responce:

+IFC: 2,2

OK

Command : AT+IFC?
Responce:

+IFC: 2,2

OK

Command : ATE0
Responce:

OK

Command : AT+QURCCFG=“urcport”,“uart1”
Responce:

OK

Command : AT
Responce:

RDY

+CPIN: READY

+QUSIM: 1

AT

OK

+CFUN: 1

Command : AT+CFUN=?
Responce: AT+CFUN=?

+CFUN: (0,1,4),(0,1)

OK

+IFC: 0,0

OK

+QIND: PB DONE

Command : AT+IFC=2,2
Responce: AT+IFC=2,2

OK

Command : AT+IFC?
Responce: AT+IFC?

+IFC: 2,2

OK

Command : ATE0
Responce: ATE0

OK

Command : AT+QURCCFG=“urcport”,“uart1”
Responce:

OK

Command : AT+QCCID
Responce:

+QCCID: 8991000908580317531F

OK

Command : AT+CGMR
Responce:

EC25EFAR06A16M4G

OK

Command : AT+CPIN?
Responce:

+CPIN: READY

OK

Command : AT+QGMR
Responce:

EC25EFAR06A16M4G_20.200.20.200

OK

Command : AT+QFLDS=“RAM”
Responce:

+QFLDS: 2606080,2616320

OK

Command : AT+QFLDS
Responce:

+QFLDS: 0,0

OK

Command : AT+QFLST=“*”
Responce:

OK

*Command : AT+QFDEL=“RAM:EVENT3.TXT”
*Responce:

+CME ERROR: 418

Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
Responce:

CONNECT

+QFUPL: 0,0

+CME ERROR: 421

Command : AT+QFDEL=“RAM:EVENT3.TXT”
Responce:

OK

Command : AT+QFUPL=“RAM:EVENT3.TXT”,5120
Responce:

CONNECT

+QFUPL: 0,0

+CME ERROR: 421

Command : AT+QFDEL=“RAM:EVENT3.TXT”
Responce:

OK

CONNECT

+QFUPL: 0,0

+CME ERROR: 421