diff --git a/esphome/components/api/api_connection.cpp b/esphome/components/api/api_connection.cpp
index 1956f3119d..431be5b4dc 100644
--- a/esphome/components/api/api_connection.cpp
+++ b/esphome/components/api/api_connection.cpp
@@ -676,8 +676,10 @@ bool APIConnection::send_buffer(ProtoWriteBuffer buffer, uint32_t message_type)
     }
   }
 
-  this->client_->add(reinterpret_cast<char *>(header.data()), header.size());
-  this->client_->add(reinterpret_cast<char *>(buffer.get_buffer()->data()), buffer.get_buffer()->size());
+  this->client_->add(reinterpret_cast<char *>(header.data()), header.size(),
+                     ASYNC_WRITE_FLAG_COPY | ASYNC_WRITE_FLAG_MORE);
+  this->client_->add(reinterpret_cast<char *>(buffer.get_buffer()->data()), buffer.get_buffer()->size(),
+                     ASYNC_WRITE_FLAG_COPY);
   bool ret = this->client_->send();
   return ret;
 }
diff --git a/esphome/const.py b/esphome/const.py
index 659531ee7b..a650954a95 100644
--- a/esphome/const.py
+++ b/esphome/const.py
@@ -2,7 +2,7 @@
 
 MAJOR_VERSION = 1
 MINOR_VERSION = 16
-PATCH_VERSION = '0b2'
+PATCH_VERSION = '0b3'
 __short_version__ = f'{MAJOR_VERSION}.{MINOR_VERSION}'
 __version__ = f'{__short_version__}.{PATCH_VERSION}'
 
diff --git a/requirements.txt b/requirements.txt
index 6ed3b1819f..78aa0442b9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,5 +10,5 @@ pytz==2020.5
 pyserial==3.5
 ifaddr==0.1.7
 platformio==5.0.4
-esptool==3.0
+esptool==2.8
 click==7.1.2