I am working with a EG916Q-GL module. I’m attempting to write data to a file on the modem’s file system (UFS). I am experiencing an issue during the writing process. After sending the AT+QFWRITE command and receiving the CONNECT message, I send all the data to the modem but the modem does not respond with the +QFWRITE URC until after it times out. I do not understand what the problem is with how I’m writing data. This exact same process does work on my BG95 module. Could I please have some assistance?
Device info:
> ATI
< Quectel
< EG916Q-GL
< Revision: EG916QGLLGR01A05M04
< OK
File writing process:
> AT+QFOPEN="notes.txt"
< +QFOPEN: 1
< OK
> AT+QFWRITE=1,250000,30
< CONNECT
// Here I transfer chunks of data in 10 25,000 byte segments
// The transfer finishes right away
// 30 seconds later these URCs are received
< +QFWRITE: 247739,247739
< +CME ERROR: 421
It appears only 247,739 of 250,000 byte are received by the modem but all 250,000 bytes were sent.
Which firmware do you arrange the test?
It seems the file data were lost, due to only 247739 bytes were written successfully, but you said you transfered 250000 bytes. Which port did you use to transfer file, Main UART port or USB port? If you use Main UART port, it is high recommended to enable flow control. From software side, please set AT+IFC=2,2 to enable it. And please also confirm the hardware connection DTS/CTS is OK.
I’m using the main UART with flow control enabled on firmware EG916QGLLGR01A05M04_01.001.01.001.
What’s confusing me is the same process for transferring data does work on a BG95 module but not on the EG91 module.
Even though the module is reporting that only 247739 of 250000 bytes were received, if I send an additional single null byte 0x00, then the module will return a successful response most of the time. That’s odd because why does sending one more byte cause the module to discover the other 2260 bytes that it said weren’t sent.
@mandy.wang Do you have a suggestion on how to resolve my issue?
Upgrading to new firmware resolved this particular issue, however, now I have a new handful of new issues which I’ll create posts for 
at+qgmr
EG916QGLLGR01A05M04_A0.300.A0.300