ArduCopter Master Firmware Version Does Not Run ESC Calibration

I flashed the released build ArduCopter master firmware version to my controller, and it does not run ESC calibration. When I put throttle high and plug in the battery, I don’t see the tri-color LED light pattern, and when I power cycle the aircraft I don’t get beeps that indicate ESC calibration. The stable firmware version does calibration as expected.

Have ArduCopter master and stable branches diverged? Is it intentional that the master version not perform ESC calibration?

I first noticed the problem when I compile my own codebase forked from master, and I looked for mistakes I’m making with git or waf. Then I tried loading software versions using QGroundControl and saw the same thing.

Here’s the details:

master version: ChibiOS-MultiRotor:Arducopter V3.70-dev (commit 1c816b1f)
stable version: ChibiOS-MultiRotor:Arducopter V3.6.8 (commit 2f409678)
controller: Pixhawk1 (which QGroundControl treats as a fmuv2 board)
ground software: QGroundControl_3.5.0
aircraft configuration: F450 quadcopter with 30A ESC’s
transmitter: Taranis Q X7
receiver: FrSky X8R