diff --git a/.github/arduino-ci/Dockerfile b/.github/arduino-ci/Dockerfile
index 4221674..e7ce92a 100644
--- a/.github/arduino-ci/Dockerfile
+++ b/.github/arduino-ci/Dockerfile
@@ -4,7 +4,13 @@ ENV TZ=Europe/Warsaw
 RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
 
 RUN apt-get update && \
-  apt-get install -y curl
+  apt-get install -y \
+    curl \
+    python3 \
+    python3-pip \
+    sudo \
+    zip
+RUN apt-get clean
 
 # install arduino-cli
 RUN curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | sh
@@ -37,18 +43,13 @@ RUN arduino-cli config add board_manager.additional_urls \
   curl https://drazzy.com/package_drazzy.com_index.json >~/.arduino15/package_drazzy.com_index.json && \
   arduino-cli update
 
-RUN arduino-cli core install esp32:esp32@2.0.14
+RUN arduino-cli core install esp32:esp32
 RUN arduino-cli core install esp8266:esp8266
 RUN arduino-cli core install STMicroelectronics:stm32
 RUN arduino-cli core install rp2040:rp2040
 RUN arduino-cli core install megaTinyCore:megaavr
 
-RUN apt-get install -y \
-  python3 \
-  python3-pip \
-  sudo \
-  zip
-RUN apt-get clean
+RUN arduino-cli config set library.enable_unsafe_install true
 
 # ESP-IDF required
 RUN pip3 install pyserial
@@ -57,5 +58,3 @@ RUN cd /usr/bin && \
   ln -sf pip3 pip
 
 RUN ln -sf /bin/bash /bin/sh
-
-RUN arduino-cli config set library.enable_unsafe_install true
diff --git a/.github/workflows/arduino-builds.yml b/.github/workflows/arduino-builds.yml
index cd0239d..32976ab 100644
--- a/.github/workflows/arduino-builds.yml
+++ b/.github/workflows/arduino-builds.yml
@@ -47,7 +47,9 @@ jobs:
         example:
           - DallasTemperature
     env:
-      BUILD_FLAGS: "\
+      # -c added to make buggy esp32-arduino core happy,
+      # see: https://github.com/espressif/arduino-esp32/issues/8815
+      BUILD_FLAGS: "-c \
         -DCONFIG_PWR_CTRL_ENABLED \
         -DCONFIG_OVERDRIVE_ENABLED \
         -DCONFIG_CRC16_ENABLED \