Dear RPi Forum Team,
The same count increment issue seems to be occurring with the RPi Debug Probe.
Please see the entry here, on [WS](viewtopic.php?p=2354984#p2354964) on the topic of Headless, RPi Zero 2 W, configuration & connection guide. Please note the RPi Debug Probe (RPiDP) is now Device 007. Not Device 006 as one would expect.
In this scenario the RPiDP had been plugged into the Dell Ubuntu host once before. So twice in total. So USB device count had been incremented by two (2) . The expectation, possibly a naive one, was that unplugging the RPiDP, after the first time it was plugged in, would have decremented the USB count by one (1) .
And plugging in the RPiDP a third time, on a host that has not been rebooted, increments the count again by one (1) to three (3) in total. The RPiDP is now Device 008.
```
$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 0cf3:e300 Qualcomm Atheros Communications QCA61x4 Bluetooth 4.0
Bus 001 Device 003: ID 138a:0091 Validity Sensors, Inc. VFS7552 Touch Fingerprint Sensor
Bus 001 Device 004: ID 04f3:24a1 Elan Microelectronics Corp. Touchscreen
Bus 001 Device 005: ID 0c45:6713 Microdia Integrated_Webcam_HD
Bus 001 Device 008: ID 2e8a:000c Raspberry Pi Debug Probe (CMSIS-DAP)
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
```
Please note the USB device number 8 using xhci_hcd .
```
$ sudo dmesg | grep -i usb
[85619.753294] usb 1-2: new full-speed USB device number 8 using xhci_hcd
[85619.878791] usb 1-2: New USB device found, idVendor=2e8a, idProduct=000c, bcdDevice= 1.01
[85619.878805] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[85619.878811] usb 1-2: Product: Debug Probe (CMSIS-DAP)
[85619.878816] usb 1-2: Manufacturer: Raspberry Pi
[85619.878821] usb 1-2: SerialNumber: E663AC91D3934132
[85619.884092] cdc_acm 1-2:1.1: ttyACM0: USB ACM device
```
Yours,
York
The same count increment issue seems to be occurring with the RPi Debug Probe.
Please see the entry here, on [WS](viewtopic.php?p=2354984#p2354964) on the topic of Headless, RPi Zero 2 W, configuration & connection guide. Please note the RPi Debug Probe (RPiDP) is now Device 007. Not Device 006 as one would expect.
In this scenario the RPiDP had been plugged into the Dell Ubuntu host once before. So twice in total. So USB device count had been incremented by two (2) . The expectation, possibly a naive one, was that unplugging the RPiDP, after the first time it was plugged in, would have decremented the USB count by one (1) .
And plugging in the RPiDP a third time, on a host that has not been rebooted, increments the count again by one (1) to three (3) in total. The RPiDP is now Device 008.
```
$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 0cf3:e300 Qualcomm Atheros Communications QCA61x4 Bluetooth 4.0
Bus 001 Device 003: ID 138a:0091 Validity Sensors, Inc. VFS7552 Touch Fingerprint Sensor
Bus 001 Device 004: ID 04f3:24a1 Elan Microelectronics Corp. Touchscreen
Bus 001 Device 005: ID 0c45:6713 Microdia Integrated_Webcam_HD
Bus 001 Device 008: ID 2e8a:000c Raspberry Pi Debug Probe (CMSIS-DAP)
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
```
Please note the USB device number 8 using xhci_hcd .
```
$ sudo dmesg | grep -i usb
[85619.753294] usb 1-2: new full-speed USB device number 8 using xhci_hcd
[85619.878791] usb 1-2: New USB device found, idVendor=2e8a, idProduct=000c, bcdDevice= 1.01
[85619.878805] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[85619.878811] usb 1-2: Product: Debug Probe (CMSIS-DAP)
[85619.878816] usb 1-2: Manufacturer: Raspberry Pi
[85619.878821] usb 1-2: SerialNumber: E663AC91D3934132
[85619.884092] cdc_acm 1-2:1.1: ttyACM0: USB ACM device
```
Yours,
York
Statistics: Posted by York Earwaker — Wed Dec 24, 2025 12:21 pm