diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 91b2aa7..4044c14 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -31,7 +31,6 @@ jobs:
     - name: Build firmware for STM32F4
       run: |
         arduino-cli core install STMicroelectronics:stm32 --additional-urls https://github.com/stm32duino/BoardManagerFiles/raw/main/package_stmicroelectronics_index.json  
-        arduino-cli lib install "Preferences"
         make BOARD=STMicroelectronics:stm32:GenF4
     - name: Upload binaries
       uses: actions/upload-artifact@v4
diff --git a/flix/parameters.ino b/flix/parameters.ino
index 4594c3e..642cfbf 100644
--- a/flix/parameters.ino
+++ b/flix/parameters.ino
@@ -3,7 +3,7 @@
 
 // Parameters storage in flash memory
 
-#include <Preferences.h>
+#include "prefs.h"
 #include "util.h"
 
 extern int channelZero[16], channelMax[16];
diff --git a/flix/prefs.h b/flix/prefs.h
new file mode 100644
index 0000000..7fb8531
--- /dev/null
+++ b/flix/prefs.h
@@ -0,0 +1,283 @@
+#ifdef ESP32
+#include <Preferences.h>
+#else
+
+#include <Arduino.h>
+#include <EEPROM.h>
+#include <string.h>
+
+class Preferences {
+public:
+	Preferences() = default;
+	~Preferences() = default;
+
+	bool begin(const char *name, bool readOnly = false, const char *partition_label = NULL) {
+		(void)name;
+		(void)readOnly;
+		(void)partition_label;
+		load();
+		started = true;
+		return true;
+	}
+
+	void end() {
+		started = false;
+	}
+
+	bool clear() {
+		if (!started) return false;
+		for (auto &entry : entries) {
+			entry = Entry();
+		}
+		return save();
+	}
+
+	size_t putFloat(const char *key, float value) {
+		if (!started) return 0;
+		int index = ensureKey(key);
+		if (index < 0) return 0;
+		entries[index].hasFloat = true;
+		entries[index].hasString = false;
+		entries[index].stringValue = "";
+		entries[index].floatValue = value;
+		if (!save()) return 0;
+		return sizeof(float);
+	}
+
+	float getFloat(const char *key, float defaultValue = NAN) {
+		if (!started) return defaultValue;
+		int index = findKey(key);
+		if (index < 0 || !entries[index].hasFloat) return defaultValue;
+		return entries[index].floatValue;
+	}
+
+	size_t putString(const char *key, const char *value) {
+		if (!started) return 0;
+		int index = ensureKey(key);
+		if (index < 0) return 0;
+		if (!value) value = "";
+		if (strlen(value) > MAX_STRING_LEN) return 0;
+
+		entries[index].hasString = true;
+		entries[index].hasFloat = false;
+		entries[index].stringValue = value;
+		if (!save()) return 0;
+		return entries[index].stringValue.length();
+	}
+
+	size_t putString(const char *key, String value) {
+		return putString(key, value.c_str());
+	}
+
+	String getString(const char *key, String defaultValue = String()) {
+		if (!started) return defaultValue;
+		int index = findKey(key);
+		if (index < 0 || !entries[index].hasString) return defaultValue;
+		return entries[index].stringValue;
+	}
+
+	bool isKey(const char *key) {
+		if (!started) return false;
+		return findKey(key) >= 0;
+	}
+
+private:
+	static const int MAX_ENTRIES = 128;
+	static const int MAX_KEY_LEN = 15;
+	static const int MAX_STRING_LEN = 95;
+	static const uint32_t MAGIC = 0x46504B56; // "VKPF"
+	static const uint8_t VERSION = 1;
+	static const uint8_t TYPE_FLOAT = 1;
+	static const uint8_t TYPE_STRING = 2;
+	static const int STORAGE_SIZE = 4096;
+
+	struct Entry {
+		bool used = false;
+		char key[MAX_KEY_LEN + 1] = {};
+		bool hasFloat = false;
+		float floatValue = NAN;
+		bool hasString = false;
+		String stringValue;
+	};
+
+	bool started = false;
+	Entry entries[MAX_ENTRIES];
+
+	static void writeU16(uint8_t *dst, uint16_t value) {
+		dst[0] = static_cast<uint8_t>(value & 0xFF);
+		dst[1] = static_cast<uint8_t>((value >> 8) & 0xFF);
+	}
+
+	static void writeU32(uint8_t *dst, uint32_t value) {
+		dst[0] = static_cast<uint8_t>(value & 0xFF);
+		dst[1] = static_cast<uint8_t>((value >> 8) & 0xFF);
+		dst[2] = static_cast<uint8_t>((value >> 16) & 0xFF);
+		dst[3] = static_cast<uint8_t>((value >> 24) & 0xFF);
+	}
+
+	static uint16_t readU16(const uint8_t *src) {
+		return static_cast<uint16_t>(src[0]) |
+			(static_cast<uint16_t>(src[1]) << 8);
+	}
+
+	static uint32_t readU32(const uint8_t *src) {
+		return static_cast<uint32_t>(src[0]) |
+			(static_cast<uint32_t>(src[1]) << 8) |
+			(static_cast<uint32_t>(src[2]) << 16) |
+			(static_cast<uint32_t>(src[3]) << 24);
+	}
+
+	int availableStorageSize() {
+		int n = STORAGE_SIZE;
+		if (EEPROM.length() > 0 && EEPROM.length() < n) n = EEPROM.length();
+		return n;
+	}
+
+	bool save() {
+		const int storageSize = availableStorageSize();
+		if (storageSize < 16) return false;
+
+		uint8_t buffer[STORAGE_SIZE] = {};
+		int pos = 0;
+		writeU32(buffer + pos, MAGIC);
+		pos += 4;
+		buffer[pos++] = VERSION;
+		buffer[pos++] = 0;
+		int lengthPos = pos;
+		pos += 2;
+
+		for (int i = 0; i < MAX_ENTRIES; i++) {
+			if (!entries[i].used) continue;
+			if (!entries[i].hasFloat && !entries[i].hasString) continue;
+
+			const uint8_t keyLen = static_cast<uint8_t>(strnlen(entries[i].key, MAX_KEY_LEN));
+			if (keyLen == 0) continue;
+
+			if (entries[i].hasFloat) {
+				const int recordSize = 3 + keyLen + 4;
+				if (pos + recordSize > storageSize) return false;
+
+				buffer[pos++] = TYPE_FLOAT;
+				buffer[pos++] = keyLen;
+				buffer[pos++] = 4;
+				memcpy(buffer + pos, entries[i].key, keyLen);
+				pos += keyLen;
+				float value = entries[i].floatValue;
+				memcpy(buffer + pos, &value, sizeof(value));
+				pos += sizeof(value);
+			} else if (entries[i].hasString) {
+				const uint8_t valueLen = static_cast<uint8_t>(entries[i].stringValue.length());
+				const int recordSize = 3 + keyLen + valueLen;
+				if (pos + recordSize > storageSize) return false;
+
+				buffer[pos++] = TYPE_STRING;
+				buffer[pos++] = keyLen;
+				buffer[pos++] = valueLen;
+				memcpy(buffer + pos, entries[i].key, keyLen);
+				pos += keyLen;
+				if (valueLen > 0) {
+					memcpy(buffer + pos, entries[i].stringValue.c_str(), valueLen);
+					pos += valueLen;
+				}
+			}
+		}
+
+		writeU16(buffer + lengthPos, static_cast<uint16_t>(pos));
+
+		for (int i = 0; i < storageSize; i++) {
+			EEPROM.write(i, buffer[i]);
+		}
+		EEPROM.commit();
+		return true;
+	}
+
+	void load() {
+		const int storageSize = availableStorageSize();
+		if (storageSize < 16) return;
+
+		for (auto &entry : entries) entry = Entry();
+
+		uint8_t buffer[STORAGE_SIZE] = {};
+		for (int i = 0; i < storageSize; i++) {
+			buffer[i] = EEPROM.read(i);
+		}
+
+		int pos = 0;
+		if (readU32(buffer + pos) != MAGIC) return;
+		pos += 4;
+		if (buffer[pos++] != VERSION) return;
+		pos++; // flags
+
+		const uint16_t totalLen = readU16(buffer + pos);
+		pos += 2;
+		if (totalLen < pos || totalLen > storageSize) return;
+
+		while (pos + 3 <= totalLen) {
+			const uint8_t type = buffer[pos++];
+			const uint8_t keyLen = buffer[pos++];
+			const uint8_t valueLen = buffer[pos++];
+			if (keyLen == 0 || keyLen > MAX_KEY_LEN) return;
+			if (pos + keyLen + valueLen > totalLen) return;
+
+			char key[MAX_KEY_LEN + 1] = {};
+			memcpy(key, buffer + pos, keyLen);
+			key[keyLen] = '\0';
+			pos += keyLen;
+
+			int index = ensureKey(key);
+			if (index < 0) return;
+
+			if (type == TYPE_FLOAT && valueLen == 4) {
+				float value = NAN;
+				memcpy(&value, buffer + pos, sizeof(value));
+				entries[index].hasFloat = true;
+				entries[index].hasString = false;
+				entries[index].stringValue = "";
+				entries[index].floatValue = value;
+			} else if (type == TYPE_STRING && valueLen <= MAX_STRING_LEN) {
+				char value[MAX_STRING_LEN + 1] = {};
+				if (valueLen > 0) memcpy(value, buffer + pos, valueLen);
+				value[valueLen] = '\0';
+				entries[index].hasString = true;
+				entries[index].hasFloat = false;
+				entries[index].stringValue = value;
+			}
+
+			pos += valueLen;
+		}
+	}
+
+	int findKey(const char *key) {
+		if (!key) return -1;
+		for (int i = 0; i < MAX_ENTRIES; i++) {
+			if (!entries[i].used) continue;
+			if (strncmp(entries[i].key, key, MAX_KEY_LEN + 1) == 0) return i;
+		}
+		return -1;
+	}
+
+	int ensureKey(const char *key) {
+		if (!key) return -1;
+		if (strlen(key) > MAX_KEY_LEN) return -1;
+
+		int index = findKey(key);
+		if (index >= 0) return index;
+
+		for (int i = 0; i < MAX_ENTRIES; i++) {
+			if (entries[i].used) continue;
+			entries[i].used = true;
+			entries[i].hasFloat = false;
+			entries[i].hasString = false;
+			entries[i].floatValue = NAN;
+			entries[i].stringValue = "";
+			strncpy(entries[i].key, key, MAX_KEY_LEN);
+			entries[i].key[MAX_KEY_LEN] = '\0';
+			return i;
+		}
+
+		return -1;
+	}
+};
+
+
+#endif
diff --git a/flix/wifi.ino b/flix/wifi.ino
index 778e422..0673190 100644
--- a/flix/wifi.ino
+++ b/flix/wifi.ino
@@ -8,7 +8,7 @@
 #include <WiFiUdp.h>
 #include <MacAddress.h>
 #include <ESP32_NOW_Serial.h>
-#include <Preferences.h>
+#include "prefs.h"
 #include "util.h"
 
 extern Preferences storage; // use the main preferences storage