diff --git a/esp3d/src/core/esp3d_settings.cpp b/esp3d/src/core/esp3d_settings.cpp
index 09691b73..555fe2d5 100644
--- a/esp3d/src/core/esp3d_settings.cpp
+++ b/esp3d/src/core/esp3d_settings.cpp
@@ -26,6 +26,7 @@
 #if defined(ESP_SAVE_SETTINGS)
 #include "esp3d_message.h"
 #include "esp3d_settings.h"
+#include "esp3d_string.h"
 
 #if ESP_SAVE_SETTINGS == SETTINGS_IN_EEPROM
 #include <EEPROM.h>
@@ -386,7 +387,7 @@ bool ESP3DSettings::writeByte(int pos, const uint8_t value) {
 
 bool ESP3DSettings::is_string(const char *s, uint len) {
   for (uint p = 0; p < len; p++) {
-    if (!isPrintable(char(s[p]))) {
+    if (!esp3d_string::isPrintableChar(char(s[p]))) {
       return false;
     }
   }
@@ -431,7 +432,7 @@ const char *ESP3DSettings::readString(int pos, bool *haserror) {
   // read until max size is reached or \0 is found
   while (i < size_max && b != 0) {
     b = EEPROM.read(pos + i);
-    byte_buffer[i] = isPrintable(char(b)) ? b : 0;
+    byte_buffer[i] = esp3d_string::isPrintableChar(char(b)) ? b : 0;
     i++;
   }
 
@@ -778,7 +779,7 @@ bool ESP3DSettings::isValidStringSetting(const char *value,
   }
   // only printable char allowed
   for (size_t i = 0; i < strlen(value); i++) {
-    if (!isPrintable(value[i])) {
+    if (!esp3d_string::isPrintableChar(value[i])) {
       return false;
     }
   }
diff --git a/esp3d/src/core/esp3d_string.cpp b/esp3d/src/core/esp3d_string.cpp
index 8f8e8881..78b4f227 100644
--- a/esp3d/src/core/esp3d_string.cpp
+++ b/esp3d/src/core/esp3d_string.cpp
@@ -178,4 +178,12 @@ const char* esp3d_string::formatBytes(uint64_t bytes) {
     res = String((float)(bytes / 1024.0 / 1024.0 / 1024.0), 2) + " GB";
   }
   return res.c_str();
+}
+
+bool esp3d_string::isPrintableChar(char ch){
+ int c = static_cast<int>(ch);
+if (c==9 || (c >= 32 && c <= 126) || c>=128) {
+    return true;
+  }
+  return false;
 }
\ No newline at end of file
diff --git a/esp3d/src/core/esp3d_string.h b/esp3d/src/core/esp3d_string.h
index 2426adf8..f94668d2 100644
--- a/esp3d/src/core/esp3d_string.h
+++ b/esp3d/src/core/esp3d_string.h
@@ -27,6 +27,7 @@ const char* generateUUID(const char* seed);
 const char* getContentType(const char* filename);
 const char* encodeString(const char* s);
 const char* formatBytes(uint64_t bytes);
+bool isPrintableChar(char c);
 }  // namespace esp3d_string
 
 #endif  //_ESP3D_STRING_H
diff --git a/esp3d/src/include/esp3d_version.h b/esp3d/src/include/esp3d_version.h
index b7e485fe..aeb0261d 100644
--- a/esp3d/src/include/esp3d_version.h
+++ b/esp3d/src/include/esp3d_version.h
@@ -22,7 +22,7 @@
 #define _VERSION_ESP3D_H
 
 // version and sources location
-#define FW_VERSION "3.0.0.a226"
+#define FW_VERSION "3.0.0.a227"
 #define REPOSITORY "https://github.com/luc-github/ESP3D/tree/3.0"
 
 #endif  //_VERSION_ESP3D_H
diff --git a/esp3d/src/modules/bluetooth/BT_service.cpp b/esp3d/src/modules/bluetooth/BT_service.cpp
index 171844b4..a7b07961 100644
--- a/esp3d/src/modules/bluetooth/BT_service.cpp
+++ b/esp3d/src/modules/bluetooth/BT_service.cpp
@@ -25,6 +25,7 @@
 #ifdef BLUETOOTH_FEATURE
 #include "../../core/esp3d_commands.h"
 #include "../../core/esp3d_settings.h"
+#include "../../esp3d_string.h"
 #include "../network/netconfig.h"
 #include "BT_service.h"
 #include "BluetoothSerial.h"
@@ -215,7 +216,7 @@ void BTService::push2buffer(uint8_t *sbuf, size_t len) {
         _buffer_size++;
       }
       flushbuffer();
-    } else if (isPrintable(char(sbuf[i]))) {
+    } else if (esp3d_string::isPrintableChar(char(sbuf[i]))) {
       if (_buffer_size < ESP3D_BT_BUFFER_SIZE) {
         _buffer[_buffer_size] = sbuf[i];
         _buffer_size++;
diff --git a/esp3d/src/modules/serial/serial_service.cpp b/esp3d/src/modules/serial/serial_service.cpp
index 9c234898..049ce698 100644
--- a/esp3d/src/modules/serial/serial_service.cpp
+++ b/esp3d/src/modules/serial/serial_service.cpp
@@ -23,6 +23,8 @@
     COMMUNICATION_PROTOCOL == RAW_SERIAL || defined(ESP_SERIAL_BRIDGE_OUTPUT)
 #include "../../core/esp3d_commands.h"
 #include "../../core/esp3d_settings.h"
+#include "../../core/esp3d_string.h"
+
 #include "serial_service.h"
 
 #if COMMUNICATION_PROTOCOL == MKS_SERIAL
@@ -406,7 +408,7 @@ void ESP3DSerialService::push2buffer(uint8_t *sbuf, size_t len) {
         _buffer_size++;
       }
       flushbuffer();
-    } else if (isPrintable(char(sbuf[i]))) {
+    } else if (esp3d_string::isPrintableChar(char(sbuf[i]))) {
       if (_buffer_size < ESP3D_SERIAL_BUFFER_SIZE) {
         _buffer[_buffer_size] = sbuf[i];
         _buffer_size++;
diff --git a/esp3d/src/modules/telnet/telnet_server.cpp b/esp3d/src/modules/telnet/telnet_server.cpp
index 60536ea4..73a8863f 100644
--- a/esp3d/src/modules/telnet/telnet_server.cpp
+++ b/esp3d/src/modules/telnet/telnet_server.cpp
@@ -28,6 +28,7 @@
 #include "../../core/esp3d_commands.h"
 #include "../../core/esp3d_message.h"
 #include "../../core/esp3d_settings.h"
+#include "../../core/esp3d_string.h"
 #include "../../include/esp3d_version.h"
 #include "telnet_server.h"
 
@@ -245,7 +246,7 @@ void Telnet_Server::push2buffer(uint8_t *sbuf, size_t len) {
         _buffer_size++;
       }
       flushbuffer();
-    } else if (isPrintable(char(sbuf[i]))) {
+    } else if (esp3d_string::isPrintableChar(char(sbuf[i]))) {
       if (_buffer_size < ESP3D_TELNET_BUFFER_SIZE) {
         _buffer[_buffer_size] = sbuf[i];
         _buffer_size++;
diff --git a/esp3d/src/modules/websocket/websocket_server.cpp b/esp3d/src/modules/websocket/websocket_server.cpp
index 55dbc2e9..591bc0eb 100644
--- a/esp3d/src/modules/websocket/websocket_server.cpp
+++ b/esp3d/src/modules/websocket/websocket_server.cpp
@@ -28,6 +28,7 @@
 #include "../../core/esp3d_commands.h"
 #include "../../core/esp3d_message.h"
 #include "../../core/esp3d_settings.h"
+#include "../../core/esp3d_string.h"
 #include "../authentication/authentication_service.h"
 #include "websocket_server.h"
 
@@ -288,7 +289,7 @@ void WebSocket_Server::push2RXbuffer(uint8_t *sbuf, size_t len) {
         _RXbufferSize++;
       }
       flushRXbuffer();
-    } else if (isPrintable(char(sbuf[i]))) {
+    } else if (esp3d_string::isPrintableChar(char(sbuf[i]))) {
       if (_RXbufferSize < RXBUFFERSIZE) {
         _RXbuffer[_RXbufferSize] = sbuf[i];
         _RXbufferSize++;
diff --git a/platformio.ini b/platformio.ini
index 0adc06e9..8f7ae0ff 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -271,3 +271,28 @@ upload_speed = 115200
 extra_scripts = pre:platformIO/extra_script.py
 lib_ignore = 
     ESP32SSPD
+
+[env:esp8285]
+platform = espressif8266@4.1.0
+board = esp8285
+framework = arduino
+monitor_speed = 115200
+monitor_echo = yes
+monitor_filters = send_on_enter, colorize, esp8266_exception_decoder
+; set frequency to 160MHz
+board_build.f_cpu = 160000000L
+; set frequency to 40MHz
+board_build.f_flash = 40000000L
+board_build.flash_mode = dout 
+upload_resetmethod = ck
+board_build.ldscript = eagle.flash.1m256.ld
+build_flags = 
+    -D PIO_FRAMEWORK_ARDUINO_LWIP2_LOW_MEMORY
+    -DNONOSDK221=1
+    -DNDEBUG
+    -DVTABLES_IN_FLASH
+    -DWAVEFORM_LOCKED_PWM
+upload_speed = 115200
+extra_scripts = pre:platformIO/extra_script.py
+lib_ignore = 
+    ESP32SSPD