Cannot flash XM125 module any more

I am trying to use the XM125 pulsed radar breakout board.
Initially, I managed to flash the Acconeer Exploration Tool binary to the board from the STM32CubeProgrammer tool.
Hoever, the Exploration Tool itself gave me a timeout on the serial connection (as others are reporting too in different discussions).
I then flashed the Exploration Tool binary again, from within the Exploration Tool itself. This also seemed successful. However, the tool still gave the timeout error.

However, ever since, I am unable to flash the module again.
Both from STM32CubeProgrammer and from the Explorer Tool, I get an error saying that it cannot connect to the board in boot mode. The error message from STM32CubeProgrammer is:

Error: Activating device: KO. Please, verify the boot mode configuration and check the serial port configuration. Reset your device then try again…

From the Explorer Tool the error message is:

synchronization failed for ‘COM13’, make sure device is in DFU mode

I am pretty sure I am pressing the button in the right way and order and that the USB driver is OK.

I have tried it also on different PCs with the same result.
I am stuck on what to try next.

Any suggestions would be welcome.

First I would try a different known-good usb cable

Make sure you follow the correct button sequence and uart baud settings Flashing Firmware to the XM125 - SparkFun Qwiic Pulsed Coherent Radar Sensor Breakout - Acconeer XM125 Hookup Guide

It also might be worth trying the other tool (python exploration tool)…there are instructions @ the links on the left side of the page