You could use the OTAdrive library and use it for OTA updates. Check here for the esp32 SIM800 gsm modem OTA example.

You should provide schematic info to help help on this issue.

I have same problem. I'm using ModbusRTU library in Serial2, and it doesn't works correctly, But it works with Serial0. I've spend lot of time to realize there is some junk in RX buffer when you didn't received byte on RX pin. This problem is always in Serial2. I've made some changes in Modbus libra...

Hi
Please check the following video
https://www.youtube.com/watch?v=hS_Z1wy ... e=emb_logo
you can check the following website for more information
https://otadrive.com