The application skeleton for ESP32 (main CPU) was built on my ksIotFrameworkLib, which provides some fancy stuff like device configuration portal, MQTT support, LED management etc.

Then the E-180 module has been studied in relation to firmware update. The idea was to use ESP32S3 as a proxy to flash the module. It was challenging since there are a plethora of possible solutions.

After some trial and error, the module was flashed with the help of esp32-blackmagic, which supports the SWD protocol in addition to being primarily used for remote on-chip debugging. It was necessary to change settings to match PCB design IO numbers for SWD IO and CLK lines.

Here's the link for EFR32 firmware blobs:
https://github.com/cziter15/EZSP-Firmware