External Secure Environment Indicator

[RicMoo]

Heya!

I'm trying to add an external indicator to an ESP32 project to indicate that the device is in secure mode.

What I'm aiming for:

Two apps installed, one which is secure, tiny and does not support BLE, WiFi or anything of the sort and an "anything goes" app. Ideally, I'd like to have a custom boot loader that, when entering the secure app, turns on an LED, but not when it goes into the "anything goes" app. And obviously, the next thing that needs to be ensured is that the "anything goes" app cannot activate the LED. The app would then write to storage which mode if wants to move to and trigger a reset to switch modes.

I've been thinking of building something that uses a latch to lock the LED on/off during bootstrap and relying on the strap pins to help out, but just thought I'd reach out to see if there is an easier way or something other's know of.

Thanks!
RicMoo