IDA 7.5--The code did not work for ESP32 firmware

[lxy2343]

Recently I loaded a ESP32 bin file into IDA 7.5. IDA did not identy processor type automaticaly. So I selected "xtensa" as targget processor. After that the IDA did not show any meaningfull functions. All data were defined as unexplored. May I know how I can fix this problem. Many thanks.