Used my Powerhead and FCB1010 (with Uno4Kemper EPROM) last Sat night for a party gig, maiden voyage, overall extremely pleased, tones were great, however had a single glitch occurrence, not certain of cause. thought I should report it.
I was running in Performance mode and at the time was in Perf #2 slot 4 (which was FB1010 button 9) for next to last song ("White Wedding") and wanted to switch to slot 5 (FCB1010 switch 10/0) in same performance for final tune ("Rebel Yell"), which has some different settings (I put them next to each other for this reason). Not important. What is important is that, when I pressed the footswitch button for slot 5, nothing happened, the footswitch LED didn't light, the slot 4 switch LED stayed lit, and the slot stayed right where it was, on slot 4. So, I'm playing my parts and trying to figure out what to do at the same time. Tried it a few times, no good. Finally, during a hiatus, hit the footswitch button for slot 2 (FCB1010 button 7) and then hit the slot 5 button again (FCB1010 button 10/0) and it came on and slot 5 was selected. It only happened the one time, and at the end of the gig.
Not certain of the cause, whether it is related to the FCB1010 or something in the Kemper, but I think most likely suspects are likely the FCB1010 or the EPROM, as I don't see how the Kemper could affect slot selection, only if the MIDI engine malfunctioned somehow. Never had this problem switching from front panel, but again MIDI is not involved using the front panel controls.
Has anyone else run into this? Other than this single glitch occurrence, the rig operated flawlessly. Wish I could say the same about my playing. 
As an aside - in terms of switching delay between slots or performances using the FCB1010, had no issues whatsoever, seemed plenty quick to me, much less than a second. On the same order as switching pedals in and out on my analog pedalboard.
. As it's a rather random issue and has not been reported so far i tend to think it is UnO related.