diff --git a/README.md b/README.md
index 02e0b3abb357b..df4e121bbcbc2 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,19 @@ The MicroPython project
   <img src="https://raw.githubusercontent.com/micropython/micropython/master/logo/upython-with-micro.jpg" alt="MicroPython Logo"/>
 </p>
 
+Single core is still supported, just by adding CONFIG_FREERTOS_UNICORE=y to
+a custom sdkconfig file.
+
+for ESP32 SOLO-1 you may do this.
+
+modify file ports/esp32/boards/sdkconfig.base and add:
+
+# FreeRTOS
+CONFIG_FREERTOS_UNICORE=y
+
+it should be ok to run in unicore mode on a dual core.
+
+
 This is the MicroPython project, which aims to put an implementation
 of Python 3.x on microcontrollers and small embedded systems.
 You can find the official website at [micropython.org](http://www.micropython.org).