Will try the same with 2v11.53 on both this evening and run jeffmers harness.
You need the latest Espruino, and replace Espruino/libs/misc/stepcount.c with https://raw.githubusercontent.com/jeffmer/step-count/master/stepcount.c Then run the test harness.
@HughB started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
You need the latest Espruino, and replace Espruino/libs/misc/stepcount.c with
https://raw.githubusercontent.com/jeffmer/step-count/master/stepcount.c
Then run the test harness.