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[Web Tools][Fixed]A temporary solution has been identified for the current Web Serial API bug in the latest version of Chrome v139 that causes possible failures to write firmware using recovery tools (including other ESP Web Tools) on Macs. The same applies to all tools that use esptool-js related tools.

Created time

Aug 11, 2025 6:57 AM

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🐝[Web Tools]Chrome has released version 139.0.7258.128, restoring normal USB serial port functionality. No additional parameters are currently required for operation.

Chrome has fixed this issue, so you no longer need to use command parameters.

The current latest version (v139) of Chrome may fail to initialize when recovering the sensor firmware on a Mac. The alert reads as follows: Failed to initialize. Try resetting your device or holding the BOOT button while selecting your serial port until it starts preparing the installation.

A related cause is a change in the api code for the serial port (https://issues.chromium.org/issues/420689824#comment11)

It is currently possible to turn off this part of the code change to revert to the original functionality (v138 behavior), which allows the esp web tool to work properly, as well as our sensor recovery tool. Close all Chrome windows, then run this command in the terminal and reopen a new Chrome to restore the burn-in.

open -b com.google.Chrome --args --disable-features=SerialSplitDtrAndRts

We think Chrome may soon release a new version to fix this issue.