Make card write atomic and don't arm unless LED state is off

firmware/firmware.ino

@@ -403,7 +403,7 @@ void postState()
 			if (LOGGING) Serial.println(lockPayload);
 			String action = deserializeLockJson(lockPayload);
 
-			if (action == "arm"  && lockState == LOCK_OFF) {
+			if (action == "arm"  && lockState == LOCK_OFF && LEDState == LED_OFF) {
 				lockState = LOCK_PREARM;
 			} else if (action == "disarm") {
 				lockState = LOCK_OFF;
@@ -442,11 +442,13 @@ void getCards()
 			cardPayload += "$"; // Mark the end
 			if (LOGGING) Serial.println(cardPayload);
 
+			noInterrupts(); // commit() disables interrupts, but we want an atomic EEPROM buffer write
 			for (int i = 0; i < cardPayload.length(); i++) {
 				if (i >= EEPROM_SIZE) break;
 				EEPROM.write(i, cardPayload.charAt(i));
 			}
 			EEPROM.commit();
+			interrupts();
 
 			if (LOGGING) Serial.println("[INFO] Finished getting card data.");
 		} else {