diff --git a/docs/reference/brick/exit-program.md b/docs/reference/brick/exit-program.md
new file mode 100644
index 00000000..5500d77c
--- /dev/null
+++ b/docs/reference/brick/exit-program.md
@@ -0,0 +1,18 @@
+# exit Program
+
+Stops the program and returns to the brick menu
+
+```sig
+brick.exitProgram();
+```
+
+## Example
+
+Do a sequence of motor commands and stop the program.
+
+```blocks
+motors.largeA.run(50)
+pause(500)
+motors.stopAll()
+brick.exitProgram();
+```
\ No newline at end of file
diff --git a/fieldeditors/field_motors.ts b/fieldeditors/field_motors.ts
index e24d3338..a9212afd 100644
--- a/fieldeditors/field_motors.ts
+++ b/fieldeditors/field_motors.ts
@@ -149,9 +149,9 @@ export class FieldMotors extends Blockly.FieldDropdown implements Blockly.FieldC
     getFirstValueI11n(value: string) {
         const firstValue = this.getFirstValue(value);
         const motorOptions = {
-            'medium motor': lf('medium motor'),
-            'large motor': lf('large motor'),
-            'large motors': lf('large motors')
+            'medium motor': lf("medium motor"),
+            'large motor': lf("large motor"),
+            'large motors': lf("large motors")
         }
         return motorOptions[firstValue];
     }
diff --git a/libs/core/battery.ts b/libs/core/battery.ts
index dc26f5fb..eef02ff7 100644
--- a/libs/core/battery.ts
+++ b/libs/core/battery.ts
@@ -26,6 +26,7 @@ namespace brick {
      */
     //% blockId=brickBatteryProperty block="battery %property"
     //% group="Battery"
+    //% blockGap=8
     //% help=brick/battery-property
     export function batteryInfo(property: BatteryProperty): number {
         const info = sensors.internal.getBatteryInfo();
diff --git a/libs/core/buttons.ts b/libs/core/buttons.ts
index 134ef4e7..3033d3c0 100644
--- a/libs/core/buttons.ts
+++ b/libs/core/buttons.ts
@@ -85,7 +85,7 @@ namespace brick {
         //% blockId=buttonIsPressed
         //% parts="brick"
         //% blockNamespace=brick
-        //% weight=81 blockGap=8
+        //% weight=81
         //% group="Buttons"
         //% button.fieldEditor="brickbuttons"
         isPressed() {
diff --git a/libs/core/input.ts b/libs/core/input.ts
index 2841eb0e..c1f8d715 100644
--- a/libs/core/input.ts
+++ b/libs/core/input.ts
@@ -104,7 +104,7 @@ namespace sensors.internal {
         }
     }
 
-    function init() {
+    export function init() {
         if (sensorInfos) return
         sensorInfos = []
         for (let i = 0; i < DAL.NUM_INPUTS; ++i) sensorInfos.push(new SensorInfo(i))
@@ -137,6 +137,7 @@ namespace sensors.internal {
         buf[UartCtlOff.Port] = port
         buf[UartCtlOff.Mode] = mode
         uartMM.ioctl(IO.UART_READ_MODE_INFO, buf)
+        control.dmesg(`UART_READ_MODE_INFO ${buf.toHex()}`)
         return buf
         //let info = `t:${buf[TypesOff.Type]} c:${buf[TypesOff.Connection]} m:${buf[TypesOff.Mode]} n:${buf.slice(0, 12).toHex()}`
         //serial.writeLine("UART " + port + " / " + mode + " - " + info)
@@ -558,7 +559,7 @@ void      cUiUpdatePower(void)
     }
 
     function setUartModes() {
-        control.dmesg(`UART set modes`)
+        control.dmesg(`UART set modes ${devcon.toHex()}`)
         uartMM.ioctl(IO.UART_SET_CONN, devcon)
         const ports: number[] = [];
         for (let port = 0; port < DAL.NUM_INPUTS; ++port) {
@@ -570,7 +571,7 @@ void      cUiUpdatePower(void)
         while (ports.length) {
             const port = ports.pop();
             const status = waitNonZeroUartStatus(port)
-            control.dmesg(`UART set mode ${status} at ${port}`);
+            control.dmesg(`UART status ${status} at ${port}`);
         }
     }
 
@@ -586,6 +587,7 @@ void      cUiUpdatePower(void)
         while (true) {
             if (port < 0) return
             updateUartMode(port, mode);
+            control.dmesg(`UART_SET_CONN ${devcon.toHex()}`)
             uartMM.ioctl(IO.UART_SET_CONN, devcon)
             let status = waitNonZeroUartStatus(port)
             if (status & UART_PORT_CHANGED) {
diff --git a/libs/core/output.ts b/libs/core/output.ts
index cba65479..ea431c00 100644
--- a/libs/core/output.ts
+++ b/libs/core/output.ts
@@ -55,7 +55,7 @@ namespace motors {
         Size = 12
     }
 
-    function init() {
+    export function init() {
         if (pwmMM) return
         pwmMM = control.mmap("/dev/lms_pwm", 0, 0)
         if (!pwmMM) control.fail("no PWM file")
@@ -159,6 +159,7 @@ namespace motors {
         private _accelerationTime: number;
         private _decelerationSteps: number;
         private _decelerationTime: number;
+        private _inverted: boolean;
 
         protected static output_types: number[] = [0x7, 0x7, 0x7, 0x7];
 
@@ -176,6 +177,7 @@ namespace motors {
             this._accelerationTime = 0;
             this._decelerationSteps = 0;
             this._decelerationTime = 0;
+            this._inverted = false;
         }
 
         /**
@@ -225,9 +227,11 @@ namespace motors {
         //% help=motors/motor/set-inverted
         setInverted(inverted: boolean) {
             this.init();
-            const b = mkCmd(this._port, DAL.opOutputPolarity, 1)
-            b.setNumber(NumberFormat.Int8LE, 2, inverted ? 0 : 1);
-            writePWM(b)
+            this._inverted = inverted;
+        }
+
+        protected invertedFactor(): number {
+            return this._inverted ? -1 : 1;
         }
 
         /** 
@@ -294,8 +298,9 @@ namespace motors {
         }
 
         private normalizeSchedule(speed: number, step1: number, step2: number, step3: number, unit: MoveUnit): MoveSchedule {
+            // motor polarity is not supported at the firmware level for sync motor operations
             const r: MoveSchedule = {
-                speed: Math.clamp(-100, 100, speed >> 0),
+                speed: Math.clamp(-100, 100, speed | 0) * this.invertedFactor(),
                 useSteps: true,
                 steps: [step1 || 0, step2 || 0, step3 || 0]
             }
@@ -562,6 +567,7 @@ namespace motors {
 
         private __init() {
             this.setOutputType(this._large);
+            this.setInverted(false);
         }
 
         /**
@@ -741,7 +747,7 @@ namespace motors {
         //% help=motors/synced/steer
         steer(turnRatio: number, speed: number, value: number = 0, unit: MoveUnit = MoveUnit.MilliSeconds) {
             this.init();
-            speed = Math.clamp(-100, 100, speed >> 0);
+            speed = Math.clamp(-100, 100, speed >> 0) * this.invertedFactor();
             if (!speed) {
                 this.stop();
                 return;
diff --git a/libs/ev3/brick.ts b/libs/ev3/brick.ts
new file mode 100644
index 00000000..16c073ef
--- /dev/null
+++ b/libs/ev3/brick.ts
@@ -0,0 +1,13 @@
+namespace brick {
+    /**
+     * Exits the program to the main menu. (in the simulator restarts it)
+     */
+    //% blockId=loopstop block="exit program"
+    //% help=reference/brick/exit-program
+    //% weight=10
+    //% blockGap=8
+    //% group="Buttons"
+    export function exitProgram() {
+        control.reset();
+    }
+}
\ No newline at end of file
diff --git a/libs/ev3/ns.ts b/libs/ev3/ns.ts
index 71c4dfe4..89e02bc1 100644
--- a/libs/ev3/ns.ts
+++ b/libs/ev3/ns.ts
@@ -1,6 +1,6 @@
 
 //% color="#68C3E2" weight=100 icon="\uf106"
-//% groups='["Buttons", "Screen", "Battery"]'
+//% groups='["Buttons", "Screen", "Power"]'
 //% labelLineWidth=60
 namespace brick {
 }
diff --git a/libs/ev3/pxt.json b/libs/ev3/pxt.json
index 1f7c4746..a54af080 100644
--- a/libs/ev3/pxt.json
+++ b/libs/ev3/pxt.json
@@ -2,8 +2,9 @@
     "name": "ev3",
     "description": "The EV3 library",
     "files": [
-        "README.md",
+        "README.md",        
         "ns.ts",
+        "brick.ts",
         "startup.ts",
         "images.jres",
         "images.ts",
diff --git a/libs/ev3/startup.ts b/libs/ev3/startup.ts
index 93941d60..8a48a002 100644
--- a/libs/ev3/startup.ts
+++ b/libs/ev3/startup.ts
@@ -2,9 +2,5 @@
 console.addListener(function(msg: string) {
     control.dmesg(msg.substr(0, msg.length - 1))
 })
-// pulse green, play startup sound, turn off light
-brick.setStatusLight(StatusLight.GreenPulse);
-// We pause for 100ms to give time to read sensor values, so they work in on_start block
-pause(400)
-// and we're ready
-brick.setStatusLight(StatusLight.Off);
+
+brick.showBoot();
\ No newline at end of file
diff --git a/libs/screen/targetoverrides.ts b/libs/screen/targetoverrides.ts
index 3cb991c9..53cb1742 100644
--- a/libs/screen/targetoverrides.ts
+++ b/libs/screen/targetoverrides.ts
@@ -129,8 +129,8 @@ namespace brick {
 
         screenMode = ScreenMode.Ports;
         renderPorts();
-        control.runInParallel(function() {
-            while(screenMode == ScreenMode.Ports) {
+        control.runInParallel(function () {
+            while (screenMode == ScreenMode.Ports) {
                 renderPorts();
                 pause(50);
             }
@@ -140,8 +140,20 @@ namespace brick {
     function renderPorts() {
         const col = 44;
         const lineHeight8 = image.font8.charHeight + 2;
+        const h = screen.height;
+        const w = screen.width;
+        const blink = (control.millis() >> 5) % (h - 1);
+
         clearScreen();
 
+        for (let i = 0; i < 4; ++i) {
+            const x = i * col + 2;
+            screen.print("ABCD"[i], x, 1 * lineHeight8, 1, image.font8)
+            screen.print((i + 1).toString(), x, h - lineHeight8, 1, image.font8)
+        }
+        screen.drawLine(0, 5 * lineHeight8, screen.width, 5 * lineHeight8, 1);
+        screen.drawLine(0, h - 5 * lineHeight8, screen.width, h - 5 * lineHeight8, 1)
+
         function scale(x: number) {
             if (Math.abs(x) >= 5000) {
                 const k = Math.floor(x / 1000);
@@ -155,25 +167,38 @@ namespace brick {
         const datas = motors.getAllMotorData();
         for (let i = 0; i < datas.length; ++i) {
             const data = datas[i];
+            const x = i * col + 2;
             if (!data.actualSpeed && !data.count) continue;
-            const x = i * col;
-            screen.print("ABCD"[i], x + 2, 1 * lineHeight8, 1, image.font8)
-            screen.print(`${scale(data.actualSpeed)}%`, x + 2, 3 * lineHeight8, 1, image.font8)
-            screen.print(`${scale(data.count)}>`, x + 2, 4 * lineHeight8, 1, image.font8)
+            screen.print(`${scale(data.actualSpeed)}%`, x, 3 * lineHeight8, 1, image.font8)
+            screen.print(`${scale(data.count)}>`, x, 4 * lineHeight8, 1, image.font8)
         }
-        screen.drawLine(0, 5 * lineHeight8, screen.width, 5 * lineHeight8, 1);
 
         // sensors
         const sis = sensors.internal.getActiveSensors();
-        const h = screen.height;
-        screen.drawLine(0, h - 5 * lineHeight8, screen.width, h - 5 * lineHeight8, 1)
         for (let i = 0; i < sis.length; ++i) {
             const si = sis[i];
-            const x = (si.port() - 1) * col;
+            const x = (si.port() - 1) * col + 2;
             const inf = si._info();
-            screen.print(si.port() + "", x, h - 4 * lineHeight8, 1, image.font8)
-            screen.print(inf, x, h - 2 * lineHeight8, 1, inf.length > 4 ? image.font5 : image.font8);
+            if (inf)
+                screen.print(inf, x, h - 2 * lineHeight8, 1, inf.length > 4 ? image.font5 : image.font8);
         }
+
+        // alive dot
+        screen.setPixel(w - 1, blink, 1);
+        screen.setPixel(w - 1, blink - 1, 1);
+        screen.setPixel(w - 2, blink - 1, 1);
+        screen.setPixel(w - 2, blink, 1);
+    }
+
+    export function showBoot() {
+        // pulse green, play startup sound, turn off light
+        brick.setStatusLight(StatusLight.GreenPulse);
+        // We pause for 100ms to give time to read sensor values, so they work in on_start block
+        sensors.internal.init();
+        motors.init();
+        pause(800);
+        // and we're ready
+        brick.setStatusLight(StatusLight.Off);
     }
 
     /**
diff --git a/sim/state/motornode.ts b/sim/state/motornode.ts
index 15c0fb2f..6cc34bb7 100644
--- a/sim/state/motornode.ts
+++ b/sim/state/motornode.ts
@@ -9,7 +9,6 @@ namespace pxsim {
         private angle: number = 0;
         private tacho: number = 0;
         private speed: number = 0;
-        private polarity: number = 1; // -1, 1 or -1
 
         private started: boolean;
         private speedCmd: DAL;
@@ -31,7 +30,7 @@ namespace pxsim {
         }
 
         getSpeed() {
-            return Math.round(this.speed * (!this._synchedMotor && this.polarity == 0 ? -1 : 1));
+            return Math.round(this.speed);
         }
 
         getAngle() {
@@ -82,16 +81,6 @@ namespace pxsim {
             return this.id == NodeType.LargeMotor;
         }
 
-        setPolarity(polarity: number) {
-            // Either 1 or 255 (reverse)
-            /*
-                -1 : Motor will run backward  
-                0 : Motor will run opposite direction  
-                1 : Motor will run forward             
-            */
-            this.polarity = polarity;
-        }
-
         reset() {
             // not sure what reset does...
         }
diff --git a/sim/state/output.ts b/sim/state/output.ts
index b3d10bbf..e059e318 100644
--- a/sim/state/output.ts
+++ b/sim/state/output.ts
@@ -119,11 +119,7 @@ namespace pxsim {
                             return 2;
                         }
                         case DAL.opOutputPolarity: {
-                            // reverse
-                            const port = buf.data[1];
-                            const polarity = pxsim.BufferMethods.getNumber(buf, BufferMethods.NumberFormat.Int8LE, 2);
-                            const motors = ev3board().getMotor(port);
-                            motors.forEach(motor => motor.setPolarity(polarity));
+                            console.error("opOutputPolarity not supported");
                             return 2;
                         }
                         case DAL.opOutputSetType: {