GSM & STM32 file download via FTP

[sne_123]

GSM modem is attached to STM32. Using FTP AT commands I am able to download a particular file from FTP server. Now I don't know where this downloaded file is saved inside the GSM modem. My goal is to transfer that file into STM32 and upgrade the firmware. Can anyone help how to do this??? 

[After Forever]

All depends on your particular GSM modem model. Read its documentation about the supported AT commands.

For example, SIM900 has this application note with an example (section 3 - FTP Application) - http://mt-system.ru/sites/default/files/sim900_ip_application_note_v1.03.pdf

[sne_123]

Thank you.I am able to get the file through FTP process and view its contents , but I am not sure where it is saving or how to save the file in the modem.

[After Forever]

The modem doesn't have the whole file per se. What if the file is 1GB or more? You wouldn't expect the modem to have a 1GB of storage space to download the file for you.

You must download the file by parts (chunks) using the AT+FTPGET command, then use/store wherever you want to. I.e. download first 1024 bytes, check the checksum, if it's OK, write to flash. Process to the next 1024 bytes, etc.

[sne_123]

@After Forever​  Do you mean I should save the file on SD card or EEprom via FTP commands of GSM modem and then allow stm32 to access the file from SD card??