POD X3 Live. Got Gearbox installed on El Capitan, but I (unfortunately) updated the firmware on the X3 Live first. Now Gearbox won't recognize it. If I go through the right permutations and dances and stand just so while holding my finger up like an antenna, I can sometimes get it to see the X3 and download tones from it, but it will mess up at least one (usually the active one,) won't download a second time, and cannot upload. So not a lot of good to me.
I tried getting the latest, greatest Parallels (with a Windows 8.1 VM) and installing there (to test the "Works on Windows! It's Apple's fault!" theory). No love there - Windows will not even see that the device is connected. That's not exactly true - Windows sees the X3, and even tries to install a driver, but Monkey and Gearbox draw a blank. Tried an old version of each and the latest version of Monkey, and none of them work. It appears to be a driver error. It is trying to use L6PODX3LV.sys v.188.8.131.52, which seems pretty stale - perhaps the updated firmware doesn't play well with that driver? So I updated to a later one - v.184.108.40.206 - and it says the device cannot start.
Next, I'll try connecting it to the old PC that I used to use it on, and see if that has better mileage. But in the meantime - if Line 6 is not going to support the device in this configuration, and no longer has a business reason to protect the software, will it at least release the specs or (better!) open source the software? This functionality is a huge part of what makes the X3 Live useful to me. It is also the only reason to participate in the CustomTone fora. It seems like opening doors to increasing user engagement should be an attractive thing.