I don’t know that this problem is exclusive to power, and I think you’re on to something with the version of the USB flash. I have had a significant amount of my probes (all from the same batch) all stop working due to USB flash drives failing, and all of them have reliable power in stable environments. I ended up replacing the USB drives in the ones I could get access to or had the host replace the USB sticks which has resolved the issue in every case. FWIW, I replaced them with Sandisk USB drives.