This is not a good fix, but apparently it works. After hours of poking around in the forums, I finally found the *one* post (and it wasn't from Logitech, it was on overclockers.net) that gave some insight into the problem. The Logitech programmable devices can reach a state where they are truly fucked (SYSTATE = "_TRULY_FHUQUED") and the drivers should be reinstalled. However, a UEFI bios sits between a device and the operating system, and manages its own set of drivers and device IDs. A Logitech programmable controller can accept a virtual ID from an OS that is different from it's hard ID, and amongst all of this you can pseudo-brick your device so that it is talking to the system with a virtual ID that isn't recognized by any windows process.

The solution is wonky but it makes some sense - uninstall your drivers, disconnect the devices, and restart twice (so that both the BIOS and Windows agree the device is gone.) After the second reboot re-attach all your devices, install your drivers, and restart again.

Should you have to do that? I dunno, but after last night I was just happy the fucker worked.

-- Peotr