ESP8266 (ESP-01) Not booting with load on IO pin 2
Simply invert the logic - so that LOW turns the SSR on and HIGH turns it off.

Try something like this:







simulate this circuit &ndash; Schematic created using CircuitLab

The P-channel FET will invert the logic. Pull GPIO2 LOW and it will turn on the FET which will enable the SSR. The 10KΩ resistor keeps the GPIO pin (and the gate of the FET) HIGH at other times.

If the GPIO pin can sink enough current to directly drive the SSR you can leave out the FET:







simulate this circuit

Again the logic is inverted. Pull GPIO2 LOW to sink current through the SSR to turn it on. The resistor keeps the GPIO pin held HIGH when booting.