as above, sounds like odd USB behaviour.
loading the tau/alpha setup when only a pico is connected, would merely call the ‘usb scanning’ code , that is also used by the pico… albeit looking for a different device.
so my only guess, would be perhaps it some how woke up the usb subsystem… but no idea why, or how this would be different from repeatedly trying to load the pico setup. perhaps its was just coincidence?!
oddly, Ive also had a couple of times when my pico decides to get a bit ‘particular’ about connecting,
when it continually refuses to connect, then I do something odd/unrelated like change cables or usb ports, it then sparks into life … and then will be perfectly happy to use the original of whatever it was i swapped (e.g. usb port/cable)
its almost like the ‘bootloader’ firmware gets into an odd state, and when you eventually get it to work this clears it BUT that makes no sense, since as soon as you remove the power (unplug usb) then its completely resets…
this similarly sounds a bit ‘odd’ there really should be no reason to need to reinstall EigenD…