How to write large FTP Files via nRF9160 Serial LTE Modem FTP Implementation

[_Martin_]

Hello,

I'm currently trying to send larger FTP files (several MBytes) with the Serial LTE Modem Application (latest version).

It's possible to establish a connection to the FTP server and perform one write command to the file. But I want to append multiple writes to one file. Everytime I use put/mput/uput the file is written completely new and data is not appended...

The AT Commands currently used (after successful connection via AT+CGDONT and check with AT+CGATT?) are:

AT#XFTP="open",<username>,<password>,<hostname>

AT#XFTP="status"

AT#XFTP="binary"

AT#XFTP="put",<file> (same with mput)

Then Data is written via UART in a loop and everytime data is sent it is also written to the file but not appended.
Could you please help, this features is of high importance for our product.

Thank you

Martin

[_Martin_]

Ok seems like mput does the job of appending data, however Server says "Append/Restart not permitted, try again", I'll look after that

[_Martin_]

Ok Problem solved:
If you are using Proftp on your own Server, you have to allow Appending/Restarting FTP Transfers for these functions to work:

https://snippets.khromov.se/allow-resuming-append-restart-of-ftp-transfer-using-proftpd/

Maybe that helps if someone else encounters this problem.