When my microcontroller boots up, it keeps the Reset pin of the SIM800L low until it needs to use the module. Then it sets the Reset pin high and waits 8 seconds for all the unsolicited messages to come in "RDY +CFUN=1 SMS Ready Call Ready".
To ease the debugging process and also just to minimise surprises, I want to factory reset the SIM800L every time I bring it out of reset.
I see on Github some people using "AT&FZ" to do a factory reset, but this command seems to be undocumented in the datasheet. Another option I think is to call "AT&F" to impose the factory settings, and then to follow it with "AT&W_SAVE" to overwrite the persistent storage.
Anyone got any documentation on "AT&FZ"? Should I instead use "AT&F" with "AT&W_SAVE"?