[error] No answer to probe


Why do I sometimes get this error when uplinking a script? Restarting the board and the trying the uplink again then works.


Hi robmarkcole,

This error message comes out when the serial port is busy during the uplink phase.
Every time you have to uplink a script make sure that you have closed the serial monitor.

Hope this can help you.


OK thanks 


am getting the same erorr everytime I am trying to Uplink my code.
I have this sequence of messages:
info] Got header: Tampered firmware!!
[info] Got header: Tampered firmware!!
[info] Got header: Tampered firmware!!
[info] Got header: Tampered firmware!!
[info] Got header: Tampered firmware!!
[error] No answer to probe

I am using this module: "
JZK ESP32 scheda di sviluppo ESP-WROOM-32 ESP-32 ESP-32S 2.4GHz WiFi + bluetooth dual mode modulo antenna con potenza ultra bassa"
My understandin is that it is supported as its “WROOM”.
I used a nodeMCU 8255 LORA and it worked very smooth but I need to upgrade to ESP32 as its more powerful.
Is there any chance I can use my board with Zerynth or should I return it ?
Virtualization went fine.



I have an update on m y last post - I re- virtualized the device and now the error is gone. Though the console is not showing anything when running the wifi examples… I will post the relevant use case in the relevant thread though,


I have found that the window of time that the uploader waits after requesting you to reset the board is very narrow. It’s easy to miss so is there a way to make it longer ??

Also if you DO miss the window and have to go again. Zerynth always re-compiles and prepares new byte code even though I haven’t changed any source. Is that really necessary ???


Hi @w1bworx,

since reset time is dependent on the board, can you tell me which one are you using? We could try to make it longer for that specific board.

For what concerns bytecode compilation, it gets recompiled every time because usually the compilation process is really fast: for this reason a cache mechanism has not been implemented yet.
On the other hand, in hybrid C/Python project, C compilation, which usually takes much time, is only performed when a change is detected.


Hi Lorenzo.
Thankyou for responding, took you a while though have you been on holiday ??

We are currently using Pycom WiPy3.0 but eventually plan to switch to the OEM module version of this board.
Board reset is a manual process and a bit fiddly so I have now gotten in the habit of finding the tiny reset switch and getting my finger ready before pushing the upload button on Zerynth. There are still times when I miss it though so I don’t think it would hurt to make the timeout maybe even twice as long as now.

Understood about bytecode compilation time, it does seem fairly fast even with a fairly large amount of python code. We are now in the process of introducing much more native C code , definitely helps speed things up. I tend to keep C in a number of small files so hopefully we are seeing the benefits here with smarter compilation. I will look out for it now that I understand !