     DEBUG_SERIAL_PRINT_FLASHSTRING("T: ");
     DEBUG_SERIAL_PRINT(heat);
     DEBUG_SERIAL_PRINTLN();
-    const uint8_t rh = RelHumidity.read();
-    DEBUG_SERIAL_PRINT_FLASHSTRING("RH%: ");
-    DEBUG_SERIAL_PRINT(rh);
-    DEBUG_SERIAL_PRINTLN();
+// SHT21 not present by default.
+//    const uint8_t rh = RelHumidity.read();
+//    DEBUG_SERIAL_PRINT_FLASHSTRING("RH%: ");
+//    DEBUG_SERIAL_PRINT(rh);
+//    DEBUG_SERIAL_PRINTLN();
     const int light = AmbLight.read();
     DEBUG_SERIAL_PRINT_FLASHSTRING("L: ");
     DEBUG_SERIAL_PRINT(light);

void panic()
{
    // Reset radio and go into low-power mode.
    PrimaryRadio.panicShutdown();
    // Power down almost everything else...
    OTV0P2BASE::minimisePowerWithoutSleep();
    pinMode(OTV0P2BASE::LED_HEATCALL_L, OUTPUT);

 * 20161111/0e6ec96     REV7:   1.5 (1.1) @ 2.5 V       REV11:  0.45 (0.03) @ 2.5 V
 * 20161111/f2eed5e     REV7:   0.46 (0.04) @ 2.5 V
 */
 
