diff --git a/README_BuildProcess.md b/README_BuildProcess.md
index 4ae1e651e..23f3e3363 100644
--- a/README_BuildProcess.md
+++ b/README_BuildProcess.md
@@ -117,7 +117,9 @@ This is a partial list of definitions that can be added in a `BOARD.py` file's `
 * `DUMP_IGNORE_VARIABLES="...\0"` - string containing zero-terminated list of global variable names to ignore when `dump()` is called. Must be explicityly zero-terminated so there are 2 trailing 0s
 * `FSMC_BITBANG` - if using a built-in FSMC Graphics LCD, don't use the hardware but instead do it in software
 * `FLASH_64BITS_ALIGNMENT=1` -  For testing 64 bit flash writes on linux
-* `JSMODULESOURCES+=libs/.../foo.min.js` - include the given JS file as a module that can be used via `require("foo")`
+* `JSMODULESOURCES+=libs/js/.../foo.min.js` - include the given JS file as a module that can be used via `require("foo")`
+  * `JSMODULESOURCES+=ModuleName:libs/js/.../module.min.js` - include as a module used with `require("ModuleName")`
+  * `JSMODULESOURCES+=_:libs/js/.../boot.min.js` - include as a file that's run at boot time
 * `JSVAR_MALLOC` - Allocate space for variables at jsvInit time, rather than statically
 * `JSVAR_FORCE_16_BYTE` - Force 16 byte JsVars (rather than packing bits to get JsVar size down to the minimum possible)
 * `USE_FONT_6X8=1` - Also include in a 6x8 fixed width bitmap font
diff --git a/boards/CURIO.py b/boards/CURIO.py
index a6b40db6e..11328cebc 100644
--- a/boards/CURIO.py
+++ b/boards/CURIO.py
@@ -80,6 +80,7 @@
      'INCLUDE += -I$(ROOT)/libs/misc',
      'WRAPPERSOURCES += libs/misc/jswrap_curio.c',
      'WRAPPERSOURCES += libs/joltjs/jswrap_qwiic.c',
+     'JSMODULESOURCES += _:libs/js/misc/curio.js'
    ]
  }
 };
diff --git a/libs/js/misc/curio.js b/libs/js/misc/curio.js
new file mode 100644
index 000000000..148020d36
--- /dev/null
+++ b/libs/js/misc/curio.js
@@ -0,0 +1,126 @@
+// see:
+//  libs/misc/jswrap_curio.c
+//  boards/CURIO.py
+led([0,0,0,2,2,2,0,0,0,0,0,0,0,0,0,0,0,0,2,2,2,0,0,0]);
+
+const PID = {
+  // gains
+  Pg : 0.015,
+  Ig : 0.001,
+  Dg : 0.05,
+  // min/max
+  Imin : -0.5,
+  Imax : 0.5
+};
+const CONST = {
+  MAXSPEED : 25, // steps/sec
+  MINSPEED : 15, // steps/sec - slowest we can sensibly run
+  SLOW_STEPS : 10, // how many steps before we slow down
+};
+function Motor(M1,M2) {
+  Object.assign(this,{
+    M1:M1,M2:M2,
+    aspeed : 0, // actual speed
+    rspeed : 0,   // requested speed
+    duty : 0,
+    idle : 0,
+    lastTime : getTime(), // time of last pin event
+    pwm : undefined, // PWM pin
+    direction : 0, // 1 or -1
+    odometer : 0, // how many steps have we moved?
+    // move to location
+    stepsLeft : 0,
+    stepSpeed : 0, // if set, we do a certain number of steps
+    // PID
+    err:0,
+    P:0,I:0,D:0,
+  });
+}
+Motor.prototype.setSpeed = function(speed) {
+  if (speed==0) {
+    digitalWrite([this.M1,this.M2],0);
+    this.duty = 0;
+    this.rspeed = 0;
+    this.pwm = undefined;
+    this.P = this.I = this.D = this.err = 0;
+  } else {
+    if (speed>0) {
+      this.pwm = this.M1;
+      this.direction = 1;
+    } else  if (speed<0) {
+      this.pwm = this.M2;
+      this.direction = -1;
+    }
+    this.duty = 1;
+    this.idle = 0;
+    analogWrite(this.pwm,this.duty);
+  }
+  this.rspeed = Math.abs(speed);
+};
+Motor.prototype.moveSteps = function(steps, speed) {
+  if (!speed || speed<0) speed = CONST.MAXSPEED;
+  if (steps<1) {
+    this.setSpeed(-speed);
+  } else {
+    this.setSpeed(speed);
+  }
+  this.stepSpeed = speed;
+  this.stepsLeft = Math.abs(steps);
+};
+Motor.prototype.onSensor = function(e) {"ram";
+  var d = e.time-this.lastTime;
+  if (d<0.02) return;
+  //print(d.toFixed(3));
+  this.lastTime = e.time;
+  this.odometer += this.direction;
+  if (this.stepsLeft) this.stepsLeft--;
+  this.aspeed = this.aspeed*0.6 + (0.4/d);
+  //print(this.aspeed, this.lastTime, this.idle);
+  this.idle=0;
+};
+Motor.prototype.onStep = function() {"ram";
+  this.idle++;
+  if (this.idle>10)
+    this.aspeed = this.aspeed*0.6 + (0.4 / (getTime()-this.lastTime));
+  // Stepping
+  if (this.stepSpeed) {
+    if (this.stepsLeft >= CONST.SLOW_STEPS) {
+      this.rspeed = this.stepSpeed;
+    } if (this.stepsLeft) {
+      this.rspeed = ((this.stepSpeed * this.stepsLeft / CONST.SLOW_STEPS) + CONST.MINSPEED) / 2;
+    } else {
+      this.stepSpeed = 0;
+      this.setSpeed(0);
+      // complete!
+    }
+  }
+  // PID
+  var err = this.rspeed-this.aspeed;
+  this.P = this.err * PID.Pg;
+  this.D = (err-this.err) * PID.Dg;
+  this.err = err;
+  this.I = E.clip(this.I + err * PID.Ig, PID.Imin, PID.Imax);
+  this.duty = E.clip(0.5 + this.P + this.I + this.D, 0, 1);
+  if (this.pwm)
+    analogWrite(this.pwm, this.duty);
+};
+
+L = new Motor(ML1,ML2);
+R = new Motor(MR1,MR2);
+setInterval(function() {"ram";
+  L.onStep();
+  R.onStep();
+}, 20);
+clearWatch();
+setWatch(L.onSensor.bind(L), IRL, {repeat:true, edge:0});
+setWatch(R.onSensor.bind(R), IRR, {repeat:true, edge:0});
+
+function go(l,r) {
+  L.setSpeed(l);
+  R.setSpeed(r);
+}
+function move(l,r,lspeed,rspeed) {
+  L.moveSteps(l,lspeed);
+  R.moveSteps(r,rspeed);
+}
+