I just got back a board for a deisgn I am using ESP32 Wrover module, I have an FTDI header for programming, DTR and RTS go to transistor pair as shown in espressif layouts, VCC from FTDI is not used. Now here is the wierd part, Everything runs fine and stable IF I am not using WiFi, BUT as soon as I use WiFi, board becomes unstable and freezes or resets (with no FTDI plugged in), NOW IF I plug in the FTDI, all of a sudden WHAM everything works PERFECT, No crashing, no resetting, WiFi works like a champ. Unplug the FTDI, and freeze or reset loops. Turn off WiFi function and works just fine with or without FTDI. Now even more wierd is the FTDI doesn't even need power! I can plug it in with no USB going to it, and the board runs perfectly stable, unplug it, crash. Without the FTDI plugged in I measure infinite resistence from GND to DTR / RTS, with it plugged in and not powered I measure 35M from DTR and RTS to both VCC AND GND, which results in 2.5V potential on DTR / RTS with no power to FTDI. I tried pull ups AND pull downs on DTR / RTS lines, makes no difference for stability. So I am really stumped on this one.