User's Guide

Page 16 of 20
Neuronytics Confidential. 12/14/21
Confidential
By Tarik
8. OTA FIRMWARE UPDATES
8.1. Memory management
Fig 5: Egg flash memory managment for DFU
The OTA firmware update uses a safe process where there is no risk of permanently damaging the Egg
system. The new firmware is always stored in Free memory space and verified to be authentic before being
copied in the main firmware space. And even if this later operation is unsuccessful, the DFU bootloader
remains untouched, which means the user would have to restart the firmware update process at worst
case.
The default behavior of Nordic semi DFU does not implement the notion of default factory firmware,
which means, factory reset is practically impossible using only the DFU feature of Nordic semi and should
be implemented separately.