Ahh, you've got the same unit as mine except mine has the DVD drive and yours has the bigger screen but I think they're running the exact same MCU and Software tbh, just the panel that's different and that's handled by the MCU anyway. I updated mine last night as per instructions from Xtrons. I've not observed any difference though.
I'm going to experiment with the yellow wire tonight. I will run it through the cabin to the battery as an experiment and stick an in-line fuse in there for good measure. My original plan was to run it to a fuse and tap one, but having Googled permanent live fuse E90, it's a minefield. If I can work out central locking I could use that I suppose?
The jury's out on the the yellow wire for me, because unless it has an impact on the way the unit plays with canbus, then it might be pretty much redundant other than for 'quick boot'. When shipped from the factory, the unit is setup to store the presets in the RAM memory, but in factory settings (126 to enter) you can actually set it to write all of your presets (and clock) to NAND. This means you lose absolutely nothing, except the clock which will read the previous time when you left the vehicle, but via GPS the clock updates within about 5-10 seconds of the unit booting and from cold it only takes about 20 seconds, so the impact is minimal.
I will experiment tonight, if the yellow wire fixes the canbus issues, then it needs to be wired in. I've found a hack to make the canbus stuff work, but it's just that.... a hack. Other than that, my initial impressions of the unit are very positive. The reversing sensors visualisation thing is awesome, although it sometimes doesn't clear until it detects a new obstacle which is annoying. I'm tempted now to fit a reversing camera in the boot handle
Then it's the full package really.