I have the same (or similar) problem:
Warning: Invalid DFU suffix signature
A valid DFU suffix will be required in a future dfu-util release
No DFU capable USB device available
When trying to upload the firmware using probe-run, I get the following error message:
Error: no probe was found.
Common reasons for this are faulty cables or missing permissions.
For detailed instructions, visit: https://github.com/knurling-rs/probe-run/tree/2f138c3#troubleshooting
error: process didn't exit successfully: probe-run --chip STM32H743ZITx --speed 30000 target\thumbv7em-none-eabihf\release\dual-iir (exit code: 1)
I run the device on Windows 10 and I followed the manual for getting started: https://quartiq.de/stabilizer/getting-started.html. In the process I tried using Zadig to install WinUSB driver, as it is recommended on the dfu-util web page, but I do not see Stabilizer or anything remotely similar in the list of connected devices. The BOOT jumper is shorted and to connect I use the USB port on the front panel.