Yes thankyou that was the problem.

I have 8 digital outputs(13, 12, 14, 27, 26, 25, 33, 32), 5v and Gnd connected to the module. No other connections.
Works fine without the module connected to 5V at boot.
I've used this ESP-32 in several other projects without problem = most used 5V.

Hi, I recently purchased a solid state relay module. Initially I used an Arduino Nano 33 IOT to drive the module. This worked fine. However, when I tried to use an ESP32, it wouldn't boot - flash read error 1000 If I connect the 5V line after booting (yes dodgy I know), everything works fine. Clearl...