diff --git a/.github/workflows/platformio.yml b/.github/workflows/platformio.yml
index 2d4b0a1..f529d17 100644
--- a/.github/workflows/platformio.yml
+++ b/.github/workflows/platformio.yml
@@ -2,7 +2,7 @@ name: PlatformIO CI
 
 on:
   push:
-    branches: [main, dev, feature/*]
+    branches: [main, dev]
   pull_request:
     branches: [main, dev]
 
diff --git a/platformio.ini b/platformio.ini
index 2572b93..76c2f3d 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -70,7 +70,7 @@ lib_ignore =
 
 [env:esp8266]
 platform = espressif8266
-board = esp8266
+board = esp01_1m
 framework = arduino
 monitor_speed = 115200
 upload_speed = 921600
@@ -103,7 +103,7 @@ lib_ignore =
 [env:stm32f103]
 platform = ststm32
 board = nucleo_f103rb
-framework = stm32cube
+framework = arduino
 monitor_speed = 9600
 upload_speed = 115200
 build_flags =
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..940aa06
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,44 @@
+/**
+ * Minimal LLP Protocol sketch — compiles on all supported platforms.
+ * Demonstrates frame building and parsing for CI verification.
+ */
+
+#include <Arduino.h>
+#include <llp_protocol.h>
+#include <string.h>
+
+static llp_parser_t parser;
+
+void setup() {
+    llp_parser_init(&parser);
+
+    const char* msg = "Hello LLP";
+
+    uint8_t final_payload[32];
+    uint8_t tx_buffer[64];
+
+    size_t payload_len = llp_build_final_payload(
+        final_payload,
+        sizeof(final_payload),
+        (const uint8_t*)msg,
+        (uint16_t)strlen(msg)
+    );
+
+    size_t frame_len = llp_build_frame(
+        tx_buffer,
+        sizeof(tx_buffer),
+        final_payload,
+        (uint16_t)payload_len
+    );
+
+    for (size_t i = 0; i < frame_len; i++) {
+        llp_parser_process_byte(
+            &parser,
+            tx_buffer[i],
+            millis()
+        );
+    }
+}
+
+void loop() {
+}