Interested in what the conditions were that you are experiencing a hole at 4500 rpm.
.
bike fully warmed up, try third gear, ride at 3000rpm and now just hold the throttle on its end stop and feel how the bike accelerates... (quite perversely any UK fuel you like never had any impact whatsoever)
the stock bike would feel rough and hesitate a bit at 4400 to 4800 rpm and hold back in higher gears around here (taking longer to accelerate through this phase of the rev range than it should)
same BMW map, CAT sensors off and my PC3 mapping, it would go through this point without a care other than rough feel, no power or torque drop (any gear, any revs, any throttle) linear curve of perfectness from 2500 to 7800 rpm.
later BMW map and my PC3 I now had a massive 1500 rpm lag the bike struggled to get past from 4000 to 5500 RPM. Struggling through that disaster the bike had far less power from 5600 rpm and didn’t want to get past 7000 rpm I spent 6 month trying any and radical PC3 fuelling to try and irradiate it... I could slightly lessen but not remove.
Fitted 4 new coils, perceived change with better smoothness but performance was even worse ! Raised a puma case and went back to zero map and refitted CAT sensors waiting for the slot in the workshop. Shocked how this change made the later map quite good below 4000 rpm. But performance from 4000 was that of an F800 with glitches and jerks that I hated and no top end at all.
Got the bike back from BMW they would not revert back to the original map. But somehow they did something (adoptions??) and the 1500 rpm hole was far smaller. Closer to the original 500 rpm hole, so it’s now similar but 20% worse than the original map that you could work around by changing the fuelling. But now you can’t fix by fuel map changes, I believe they now knobble the ignition curve and I can’t get at that. Top end when I first got it back from puma case was nothing. I was going to ride back and hand the bike back..... but as I accelerated hard it picked up a bit, over the next 3 miles it woke up and was almost back making proper power and revving out cleanly. Odd, I guess it was some adaption thing but I don’t understand it.
But the original map and my PC3 mapping was still way better. I actually bought another ECU with exact part numbers (hoping its got the right map, but need to code out old immobiliser and then hack the mileage back to match mine....) that’s another story – I have the car based tools to do it and videos of how.... but although the ECU is listed under BMW car tools but the map I want isn’t