diff --git a/lib/patrix/config.cpp b/lib/patrix/config.cpp
index 393e017..ac9f866 100644
--- a/lib/patrix/config.cpp
+++ b/lib/patrix/config.cpp
@@ -128,7 +128,7 @@ bool configWriteBytes(int *address, uint8_t *data, size_t size) {
       break;
     }
   }
-  return b - data == size;
+  return (size_t) (b - data) == size;
 }
 
 bool configReadBytes(int *address, uint8_t *data, size_t size) {
@@ -140,5 +140,5 @@ bool configReadBytes(int *address, uint8_t *data, size_t size) {
       break;
     }
   }
-  return b - data == size;
+  return (size_t) (b - data) == size;
 }
diff --git a/lib/patrix/console.cpp b/lib/patrix/console.cpp
index cb10909..833adc1 100644
--- a/lib/patrix/console.cpp
+++ b/lib/patrix/console.cpp
@@ -68,6 +68,10 @@ void consoleLoop() {
 
 void consoleHandle(char *cmd) {
   char *first = strtok(cmd, " ");
+  if (first == nullptr) {
+    _usage();
+    return;
+  }
   if (strcmp(first, "help") == 0) {
     _usage();
   } else if (strcmp(first, "wifi") == 0) {
@@ -88,19 +92,18 @@ void consoleHandle(char *cmd) {
 }
 
 void _usage() {
-  info("help");
-  info("info");
-  info("debug");
-
-  info("reboot");
-  info("config_reset");
-
-  info("wifi reconnect");
-  info("wifi ssid <SSID>");
-  info("wifi pkey <PKEY>");
-
-  info("mqtt reconnect");
-  info("mqtt host <HOST>");
+  info(R"(USAGE:
+  help
+  info
+  debug
+  reboot
+  config_reset
+  wifi reconnect
+  wifi ssid <SSID>
+  wifi pkey <PKEY>
+  mqtt reconnect
+  mqtt host <HOST>
+)");
 }
 
 void _debug() {
@@ -117,6 +120,10 @@ void _reboot() {
 
 void _mqtt() {
   char *sub = strtok(nullptr, " ");
+  if (sub == nullptr) {
+    _usage();
+    return;
+  }
   if (strcmp(sub, "reconnect") == 0) {
     info("Reconnecting MQTT...");
     mqttDisconnect();
@@ -127,6 +134,10 @@ void _mqtt() {
 
 void _wifi() {
   char *sub = strtok(nullptr, " ");
+  if (sub == nullptr) {
+    _usage();
+    return;
+  }
   if (strcmp(sub, "reconnect") == 0) {
     info("Reconnecting WiFi...");
     wifiConnect();
@@ -139,6 +150,10 @@ void _wifi() {
 
 void _setConfigString(const char *name, bool allowEmpty) {
   char *value = strtok(nullptr, "");
+  if (value == nullptr) {
+    _usage();
+    return;
+  }
   if (!allowEmpty && strcmp(value, "") == 0) {
     error(R"(Value for "%s" cannot be empty!")", name);
     return;
diff --git a/src/Fermenter.cpp b/src/Fermenter.cpp
index e13c0b3..a8da776 100644
--- a/src/Fermenter.cpp
+++ b/src/Fermenter.cpp
@@ -82,6 +82,10 @@ void patrixLoop() {
 
 bool setDouble(const char *name, double *destinationPtr, double min, double max) {
   const char *valueStr = strtok(nullptr, "");
+  if (valueStr == nullptr) {
+    _usage();
+    return;
+  }
   if (valueStr == nullptr) {
     error("Missing value for \"%s\"", name);
     return false;