diff --git a/esphome/components/api/api_frame_helper.cpp b/esphome/components/api/api_frame_helper.cpp
index 669be8052c..90c35c3ec0 100644
--- a/esphome/components/api/api_frame_helper.cpp
+++ b/esphome/components/api/api_frame_helper.cpp
@@ -91,12 +91,14 @@ APIError APIFrameHelper::write_raw_(const struct iovec *iov, int iovcnt) {
     // Try to send the remaining data in this buffer
     ssize_t sent = this->socket_->write(front_buffer.current_data(), front_buffer.remaining());
 
-    if (this->is_would_block(sent)) {
-      // Socket would block, we'll try again later
-    } else if (sent == -1) {
-      ESP_LOGVV(TAG, "%s: Socket write failed with errno %d", this->info_.c_str(), errno);
-      this->state_ = State::FAILED;
-      return APIError::SOCKET_WRITE_FAILED;  // Socket write failed
+    if (sent == -1) {
+      if (errno != EWOULDBLOCK && errno != EAGAIN) {
+        // Real socket error (not just would block)
+        ESP_LOGVV(TAG, "%s: Socket write failed with errno %d", this->info_.c_str(), errno);
+        this->state_ = State::FAILED;
+        return APIError::SOCKET_WRITE_FAILED;  // Socket write failed
+      }
+      // Socket would block, we'll try again later and continue execution to append new data to the buffer
     } else if (sent > 0 && static_cast<size_t>(sent) < front_buffer.remaining()) {
       // Partially sent, update offset
       front_buffer.offset += sent;
@@ -129,19 +131,20 @@ APIError APIFrameHelper::write_raw_(const struct iovec *iov, int iovcnt) {
   // Try to send directly if no buffered data
   ssize_t sent = this->socket_->writev(iov, iovcnt);
 
-  if (this->is_would_block(sent)) {
-    // Socket would block, buffer the data
-    SendBuffer buffer;
-    buffer.data.reserve(total_write_len);
+  if (sent == -1) {
+    if (errno == EWOULDBLOCK || errno == EAGAIN) {
+      // Socket would block, buffer the data
+      SendBuffer buffer;
+      buffer.data.reserve(total_write_len);
 
-    for (int i = 0; i < iovcnt; i++) {
-      const uint8_t *data = reinterpret_cast<uint8_t *>(iov[i].iov_base);
-      buffer.data.insert(buffer.data.end(), data, data + iov[i].iov_len);
+      for (int i = 0; i < iovcnt; i++) {
+        const uint8_t *data = reinterpret_cast<uint8_t *>(iov[i].iov_base);
+        buffer.data.insert(buffer.data.end(), data, data + iov[i].iov_len);
+      }
+
+      this->tx_buf_.push_back(std::move(buffer));
+      return APIError::OK;  // Success, data buffered
     }
-
-    this->tx_buf_.push_back(std::move(buffer));
-    return APIError::OK;  // Success, data buffered
-  } else if (sent == -1) {
     // Socket error
     ESP_LOGVV(TAG, "%s: Socket write failed with errno %d", this->info_.c_str(), errno);
     this->state_ = State::FAILED;
@@ -184,10 +187,11 @@ APIError APIFrameHelper::try_send_tx_buf_() {
     // Try to send the remaining data in this buffer
     ssize_t sent = this->socket_->write(front_buffer.current_data(), front_buffer.remaining());
 
-    if (this->is_would_block(sent)) {
-      // Socket would block, try again later
-      break;
-    } else if (sent == -1) {
+    if (sent == -1) {
+      if (errno == EWOULDBLOCK || errno == EAGAIN) {
+        // Socket would block, try again later
+        break;
+      }
       // Socket error
       state_ = State::FAILED;
       ESP_LOGVV(TAG, "%s: Socket write failed with errno %d", this->info_.c_str(), errno);
diff --git a/esphome/components/api/api_frame_helper.h b/esphome/components/api/api_frame_helper.h
index c4e7072666..15d9d8664d 100644
--- a/esphome/components/api/api_frame_helper.h
+++ b/esphome/components/api/api_frame_helper.h
@@ -164,14 +164,6 @@ class APIFrameHelper {
 
   // Try to send data from the tx buffer
   APIError try_send_tx_buf_();
-
-  // Check if the socket would block based on return value
-  inline bool is_would_block(ssize_t ret) const {
-    if (ret == -1) {
-      return errno == EWOULDBLOCK || errno == EAGAIN;
-    }
-    return ret == 0;
-  }
 };
 
 #ifdef USE_API_NOISE
diff --git a/esphome/components/api/proto.h b/esphome/components/api/proto.h
index b8ee6b7920..e110a58eda 100644
--- a/esphome/components/api/proto.h
+++ b/esphome/components/api/proto.h
@@ -20,16 +20,26 @@ class ProtoVarInt {
   explicit ProtoVarInt(uint64_t value) : value_(value) {}
 
   static optional<ProtoVarInt> parse(const uint8_t *buffer, uint32_t len, uint32_t *consumed) {
-    if (consumed != nullptr)
-      *consumed = 0;
-
-    if (len == 0)
+    if (len == 0) {
+      if (consumed != nullptr)
+        *consumed = 0;
       return {};
+    }
 
-    uint64_t result = 0;
-    uint8_t bitpos = 0;
+    // Most common case: single-byte varint (values 0-127)
+    if ((buffer[0] & 0x80) == 0) {
+      if (consumed != nullptr)
+        *consumed = 1;
+      return ProtoVarInt(buffer[0]);
+    }
 
-    for (uint32_t i = 0; i < len; i++) {
+    // General case for multi-byte varints
+    // Since we know buffer[0]'s high bit is set, initialize with its value
+    uint64_t result = buffer[0] & 0x7F;
+    uint8_t bitpos = 7;
+
+    // Start from the second byte since we've already processed the first
+    for (uint32_t i = 1; i < len; i++) {
       uint8_t val = buffer[i];
       result |= uint64_t(val & 0x7F) << uint64_t(bitpos);
       bitpos += 7;
@@ -40,7 +50,9 @@ class ProtoVarInt {
       }
     }
 
-    return {};
+    if (consumed != nullptr)
+      *consumed = 0;
+    return {};  // Incomplete or invalid varint
   }
 
   uint32_t as_uint32() const { return this->value_; }
diff --git a/requirements.txt b/requirements.txt
index 106a6ff901..c89ad4a6e4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -19,7 +19,7 @@ puremagic==1.29
 ruamel.yaml==0.18.10 # dashboard_import
 esphome-glyphsets==0.2.0
 pillow==10.4.0
-cairosvg==2.8.0
+cairosvg==2.8.1
 freetype-py==2.5.1
 
 # esp-idf requires this, but doesn't bundle it by default