Secure DFU, update from a remote server

[lybrus]

Hi,

I develop a device with a GPRS modem. GPRS modem is controlled by nrf52840 and it is impossible to use two devices for DFU process.

SDK: 17.0.2

SoftDevice: s140 7.2.0

My idea is:

1. Download bin and data files to nrf flash using uart (AT commands) from an HTTP server
2. Set some flag for bootloader
3. Reboot the nrf
4. Bootloader upgrades by checking this flag. Check firmware and activate new firmware (dual-bank update).

Main idea - not to bring all processes about firmware checking to the main application to reduce application size and complexity. So, questions:

• Is it a good idea or not?
• How to store bin and data files to nrf flash?
• How to set flags for the bootloader?
• How to modify the bootloader?

It would be great to have some examples or links to similar posts. Thanks in advance!

[lybrus]

Everything is ok. nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_RESET); works. I needed to wait untill nrf_dfu_settings_write_and_backup finish.