ESPEFUSE doesn't close COM port when throws an exception when called from Python (ESPTOOL-557)

[reykada]

Operating System

Windows 10 Pro 21H2

Esptool Version

v4.3

Python Version

Python 3.9.6

Chip Description

ESP32-D0WD-V3 (revision v3.0)

Device Description

NodeMCU ESP-32 v1.1

Hardware Configuration

No response

How is Esptool Run

No IDE

Full Esptool Command Line that Was Run

From Python script

Esptool Output

An exception occurred: BLOCK2 is read-protected. Burn in this case may damage an already written value.(use '--force-write-always' option to ignore it)

More Information

No response

Other Steps to Reproduce

No response

I Have Read the Troubleshooting Guide

• I confirm I have read the troubleshooting guide.

[reykada]

Hi

I use Python script which includes several subsequent calls of ESPTOOL and ESPEFUSE for production purpose.
The problem is if I do the calls like:

command = ['--port', comport, 'burn_key', 'flash_encryption', path_to_flash_enc_key, '--do-not-confirm']
espefuse.main(command)

and ESPEFUSE throws an exception which leads to my Python script termination. But I need the further ESPTOOL calls in my script to be executed.

So I decided to add exception handler:

    command = ['--port', comport, 'burn_key', 'flash_encryption', path_to_flash_enc_key, '--do-not-confirm']
    try:
        espefuse.main(command)
    except BaseException as error:
        print(f'An exception occurred: {format(error)}')

I can get and print an exception in this case:

An exception occurred: BLOCK2 is read-protected. Burn in this case may damage an already written value.(use '--force-write-always' option to ignore it)

But when ESPEFUSE is called further in my Python script I get the following error:

An exception occurred: Could not open COM3, the port doesn't exist
Please make sure that you have specified the right port with the --port argument

So looks like ESPEFUSE doesn't release the COM port when throw an exception.

ESPTOOL version: 4.3

Are there any workaround?
Regards

[radimkarnis]

Hi @reykada,
thanks for the detailed report! I will look into it and provide a fix.

[radimkarnis]

Hello @reykada,
could you please verify this patch: close_port.txt ?

To try it, please clone this repo and install it in development mode with:

cd esptool
pip install -e .

You can try your script at this point - it should still fail.

Then please download close_port.txt and apply the patch in the esptool folder with git am close_port.txt. When you try your script now, it should work.

Thank you!

[reykada]

Hi @radimkarnis

It does work! The port is being closed when ESPEFUSE throws an exception.
Thank you so much for the quick fix!

[radimkarnis]

@reykada thanks for your help and the report! The fix has been merged to master.