I have just discovered that ADC calibration has a step forward for its solution.
Infact, it seems Vref or two point calibration is stored in EFUSE blocks. However this depends on the date of production as stated in documentation.
For example I have some ESP-WROOM-32 modules bought probably one year ago and if I ask the status of EFUSE with
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We have also bougth one month ago 100 ESP-WROOM-32 for pre-series of our product and I can't test them because they need to be soldered on PCB.
The question: Which is the starting date of production which guarantees that EFUSE are written with Vref or 2-point calibration? How can I know this on ESP-WROOM-32?