diff --git a/esphome/components/ld2410/ld2410.cpp b/esphome/components/ld2410/ld2410.cpp
index a3c2193d672..f8f782f804a 100644
--- a/esphome/components/ld2410/ld2410.cpp
+++ b/esphome/components/ld2410/ld2410.cpp
@@ -601,28 +601,11 @@ void LD2410Component::readline_(int readch) {
     return;  // No data available
   }
 
-  // Frame header synchronization: verify first 4 bytes match a known frame header.
-  // This prevents the parser from getting stuck in an overflow loop after losing sync
-  // (e.g. after module restart or UART noise).
-  if (this->buffer_pos_ < HEADER_FOOTER_SIZE) {
-    const uint8_t byte = static_cast<uint8_t>(readch);
-    // Verify header bytes match the frame type established by byte 0
-    if (this->buffer_pos_ > 0) {
-      const uint8_t *expected = (this->buffer_data_[0] == DATA_FRAME_HEADER[0]) ? DATA_FRAME_HEADER : CMD_FRAME_HEADER;
-      if (byte != expected[this->buffer_pos_]) {
-        this->buffer_pos_ = 0;  // Reset and fall through to check if this byte starts a new frame
-      }
-    }
-    // First byte must match start of a data or command frame header
-    if (this->buffer_pos_ == 0 && byte != DATA_FRAME_HEADER[0] && byte != CMD_FRAME_HEADER[0]) {
-      return;
-    }
-  }
-
   if (this->buffer_pos_ < MAX_LINE_LENGTH - 1) {
     this->buffer_data_[this->buffer_pos_++] = readch;
     this->buffer_data_[this->buffer_pos_] = 0;
   } else {
+    // We should never get here, but just in case...
     ESP_LOGW(TAG, "Max command length exceeded; ignoring");
     this->buffer_pos_ = 0;
     return;
diff --git a/esphome/components/ld2420/ld2420.h b/esphome/components/ld2420/ld2420.h
index 02250c59114..358793fe64f 100644
--- a/esphome/components/ld2420/ld2420.h
+++ b/esphome/components/ld2420/ld2420.h
@@ -21,7 +21,9 @@
 namespace esphome::ld2420 {
 
 static constexpr uint8_t CALIBRATE_SAMPLES = 64;
-static constexpr uint8_t MAX_LINE_LENGTH = 46;  // Max characters for serial buffer
+// Energy frame is 45 bytes; +1 for null terminator, +4 so that a frame footer always lands
+// inside the buffer during footer-based resynchronization after losing sync.
+static constexpr uint8_t MAX_LINE_LENGTH = 50;
 static constexpr uint8_t TOTAL_GATES = 16;
 
 enum OpMode : uint8_t {
diff --git a/esphome/components/ld2450/ld2450.cpp b/esphome/components/ld2450/ld2450.cpp
index 2af45235a39..d30c1647695 100644
--- a/esphome/components/ld2450/ld2450.cpp
+++ b/esphome/components/ld2450/ld2450.cpp
@@ -769,28 +769,11 @@ void LD2450Component::readline_(int readch) {
     return;  // No data available
   }
 
-  // Frame header synchronization: verify first 4 bytes match a known frame header.
-  // This prevents the parser from accumulating mid-frame data after losing sync
-  // (e.g. after module restart or UART noise).
-  if (this->buffer_pos_ < HEADER_FOOTER_SIZE) {
-    const uint8_t byte = static_cast<uint8_t>(readch);
-    // Verify header bytes match the frame type established by byte 0
-    if (this->buffer_pos_ > 0) {
-      const uint8_t *expected = (this->buffer_data_[0] == DATA_FRAME_HEADER[0]) ? DATA_FRAME_HEADER : CMD_FRAME_HEADER;
-      if (byte != expected[this->buffer_pos_]) {
-        this->buffer_pos_ = 0;  // Reset and fall through to check if this byte starts a new frame
-      }
-    }
-    // First byte must match start of a data or command frame header
-    if (this->buffer_pos_ == 0 && byte != DATA_FRAME_HEADER[0] && byte != CMD_FRAME_HEADER[0]) {
-      return;
-    }
-  }
-
   if (this->buffer_pos_ < MAX_LINE_LENGTH - 1) {
     this->buffer_data_[this->buffer_pos_++] = readch;
     this->buffer_data_[this->buffer_pos_] = 0;
   } else {
+    // We should never get here, but just in case...
     ESP_LOGW(TAG, "Max command length exceeded; ignoring");
     this->buffer_pos_ = 0;
     return;
diff --git a/tests/components/ld2450/ld2450_readline.cpp b/tests/components/ld2450/ld2450_readline.cpp
index 66dec7a36b4..cb97f633bfb 100644
--- a/tests/components/ld2450/ld2450_readline.cpp
+++ b/tests/components/ld2450/ld2450_readline.cpp
@@ -93,10 +93,7 @@ TEST_F(LD2450ReadlineTest, CmdFooterInGarbageResyncs) {
 TEST_F(LD2450ReadlineTest, OverflowResetsBuffer) {
   // Fill the buffer to capacity with filler that won't match any footer.
   // MAX_LINE_LENGTH is 45, usable is 44. The 45th byte triggers overflow.
-  std::vector<uint8_t> overflow_data;
-  for (int i = 0; i < MAX_LINE_LENGTH; i++) {
-    overflow_data.push_back(0x11);  // Filler that won't match any footer
-  }
+  std::vector<uint8_t> overflow_data(MAX_LINE_LENGTH, 0x11);
   this->ld2450_.feed(overflow_data);
   // After overflow, buffer_pos_ resets to 0 (via the < 4 early return path)
   EXPECT_LT(this->ld2450_.buffer_pos_, 4);
@@ -104,10 +101,7 @@ TEST_F(LD2450ReadlineTest, OverflowResetsBuffer) {
 
 TEST_F(LD2450ReadlineTest, OverflowThenValidFrame) {
   // Overflow, then a valid frame should be processed.
-  std::vector<uint8_t> overflow_data;
-  for (int i = 0; i < MAX_LINE_LENGTH; i++) {
-    overflow_data.push_back(0x11);
-  }
+  std::vector<uint8_t> overflow_data(MAX_LINE_LENGTH, 0x11);
   this->ld2450_.feed(overflow_data);
 
   auto frame = make_periodic_frame();
@@ -119,11 +113,7 @@ TEST_F(LD2450ReadlineTest, BufferLargeEnoughForDesyncedFooter) {
   // The key fix: the buffer (45) is large enough that a desynced periodic frame's
   // footer (at most 30 bytes into the stream) will land inside the buffer before overflow.
   // Simulate starting 10 bytes into a periodic frame, then a full frame follows.
-  std::vector<uint8_t> mid_frame;
-  // 10 bytes of "mid-frame" data (no footer match)
-  for (int i = 0; i < 10; i++) {
-    mid_frame.push_back(0x30 + i);
-  }
+  std::vector<uint8_t> mid_frame = {0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39};
   // Then a complete periodic frame whose footer will land at position 40 (10 + 30),
   // well within the buffer size of 45.
   auto frame = make_periodic_frame();