Thanks for the info. I think I'll skip trying to overwrite the eFuse, seems more effort than it's worth. Looks like I can also use the ESP-IDF you disable the eFuse check and force the esp_adc_cal_characterize function to use the VREF parameter, but that also seems like more effort than it's worth. ...

I got a Lolin D32 and I'm trying to read the battery voltage with an Arduino sketch. It's pretty close, but seems like it's a bit more inaccurate than it should be. After hours of reading about the calibration process I came to the conclusion that the board I got came with the ADC VRef calibration e...