Thanks for the fast response! =D
Anyway i tried your method, and the same error still happen. cant upload
Yup i have a logic converter.
LV SIDE
LV1 - TX (ESP-01)
LV2 - RX (ESP-01)
LV - 3.3v (UNO)
GND - GND (UNO)
HV SIDE
HV1 - TX (UNO)
HV2 - RX (UNO)
HV - 5v (UNO)
GND - GND (UNO)