Using dtoverlay=pi3-disable-bt to disable Bluetooth results in unbootable system

[Svet Bajlekov]

The commonly documented way for disabling Bluetooth on a Raspberry Pi 3 Model B is by adding the line
dtoverlay=pi3-disable-bt
to /boot/config.txt. This works as expected on the Ubuntu Core 16 Raspberry Pi 3 "stable" image (as linked from https://developer.ubuntu.com/core/get-started/raspberry-pi-2-3).

However, for recent "edge" images - which use the pi2-kernel snap release 4.4.0-1080.88 - adding that line to config.txt leads to an unbootable system. Namely, the boot process does not even get past the initial "rainbow" screen, and no boot messages are displayed or logged. Unfortunately, due to that, there's not a whole lot I can offer in terms of further troubleshooting info.

If helpful I can attach the full config.txt file.

Many thanks for taking a look at this.