Huge thanks to
shawnsheridan and
SaNGRia for this thread, as well as
netinvader for his thread at
https://f80.bimmerpost.com/forums/sh....php?t=1585726
I successfully flashed my F30 with NBTEvo_J to NBTEvo_Y tonight and then retrofitted CarPlay via an eBay seller's ENET activation method for ~$35. I'm not sure if it's because I'm using an ancient ENET cable or the $8 USB ethernet adapter, but somehow this flash took 3 hours.
On the topic of power supplies, for future reference, I used a $55 STANLEY BC25BS with 25amp of constant output and I only saw it go to ~15 amps during the flash, and it held at 13.9-14.0V the entire time. For anyone that wants to play it safe but do not want to spend hundreds, you can buy a 66.7amp (800W) power supply that can be adjusted up to 14.6V on Amazon for $80. If you want to really play it safe, I found 100 amp power supplies from PowerMax on Amazon and eBay for $180, and you can adjust the voltage on those as well. Just search "PowerMax 100". I actually found a PowerMax PM3-100 at an RV supply store locally that price matched.