Bug: Thonny connection lost after updating to MicroHydra v 2.5

[przem360]

Description

After updating the M5Stack Cardputer firmware from MicroHydra v2.4 to v2.5, I am unable to connect to the device using the Thonny IDE. Rolling back to v2.4.

Environment

• Device: M5Stack Cardputer
• Firmware affected: MicroHydra v2.5
• Working Firmware: MicroHydra v2.4
• IDE: Thonny (Latest version)
• Operating System: Linux Mint
• Connection Method: USB-C cable (same cable used for both versions)

Steps to Reproduce

1. Use M5Burner to erase the Cardputer.
2. Burn the MicroHydra v2.5 firmware onto the Cardputer.
3. Ensure the Cardputer is powered off.
4. Connect the powered-off Cardputer to the PC via USB. (The device powers on automatically.)
5. Launch the Thonny IDE and attempt to connect to the Cardputer (usually by simply running Thonny).

Expected Behavior

Thonny should connect successfully to the Cardputer, allowing file system access and execution of MicroPython commands. This behavior is observed when running v2.4.

Observed Behavior (The Error)

When attempting to connect, Thonny reports the following error message:

Connection lost -- device reports readiness to read but returned no data (device disconnected or multiple access on port?)

Use Stop/Restart to reconnect.

Process ended with exit code 1.

Troubleshooting

• I have verified that using the exact same PC and USB cable with MicroHydra v2.4 works without any issues.
• The issue is consistently reproducible immediately after burning v2.5 and disappears immediately after rolling back to v2.4.

I looked at the settings in Thonny, under Tools > Options > Interpreter, I switched Interrupt working program on connect and Restart interpreter before running a script off and it sometimes connects. But only sometimes, now after starting Thonny I see this:

Device is busy or does not respond. Your options:

  - wait until it completes current work;
  - use Ctrl+C to interrupt current work;
  - reset the device and try again;
  - check connection properties;
  - make sure the device has suitable MicroPython / CircuitPython / firmware;
  - make sure the device is not in bootloader mode.