diff --git a/Dockerfile b/Dockerfile
index 6d79da8..e399d88 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -32,7 +32,8 @@ COPY arduino-cli.yaml /home/$USER/.arduino15/
 RUN \
   arduino-cli core update-index && \
   arduino-cli core install arduino:avr && \
-  arduino-cli core install esp8266:esp8266 
+  arduino-cli core install esp8266:esp8266@2.5.0 && \
+  sed -i 's/#if DEBUG/#ifdef DEBUG/' ~/.arduino15/packages/esp8266/hardware/esp8266/2.5.0/tools/sdk/libc/xtensa-lx106-elf/include/sys/reent.h 
   
 
 CMD ["/bin/bash"]