diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index b8569a6..eb641eb 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -15,9 +15,7 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Install Arduino CLI
-        run: |
-          curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | sh
-          sudo mv bin/arduino-cli /usr/local/bin/
+        uses: arduino/setup-arduino-cli@81d310742121c928ea9c8bbd407b4217b432ae02  # v2.0.0
 
       - name: Initialize Arduino CLI
         run: |
@@ -25,12 +23,11 @@ jobs:
           arduino-cli core update-index
 
       - name: Install required board core
-        run: arduino-cli core install arduino:avr
+        run: arduino-cli core install arduino:avr@1.8.7  # např. pro Arduino Uno
           
       - name: Install custom library
         run: |
-          mkdir -p ~/Arduino/libraries
-          git clone https://github.com/Zefek/MQTTESP8266.git ~/Arduino/libraries/MQTTESP8266
+          arduino-cli lib install "MQTTESP8266@5.1.2"
 
       - name: Set configs
         run: |
diff --git a/.github/workflows/deployment.yml b/.github/workflows/deployment.yml
index 6b9e7ef..42f3c81 100644
--- a/.github/workflows/deployment.yml
+++ b/.github/workflows/deployment.yml
@@ -19,12 +19,12 @@ jobs:
 
       - name: Install required board core
         run: | 
-          & "$Env:RUNNER_TOOL_CACHE\arduino-cli\arduino-cli.exe" --config-file config.yaml core install arduino:avr 
+          & "$Env:RUNNER_TOOL_CACHE\arduino-cli\arduino-cli.exe" --config-file config.yaml core install arduino:avr@1.8.7
           
       - name: Install custom Arduino libraries (Windows)
         shell: powershell
         run: |
-          & "$Env:RUNNER_TOOL_CACHE\arduino-cli\arduino-cli.exe" --config-file config.yaml lib install MQTTESP8266
+          & "$Env:RUNNER_TOOL_CACHE\arduino-cli\arduino-cli.exe" --config-file config.yaml lib install "MQTTESP8266@5.1.2"
 
       - name: Set configs (Windows)
         shell: powershell
@@ -38,6 +38,11 @@ jobs:
           & "$Env:RUNNER_TOOL_CACHE\arduino-cli\arduino-cli.exe" --config-file config.yaml compile --fqbn arduino:avr:uno ./ --output-dir build
 
       - name: Upload firmware to Arduino
+        env:
+          SERIAL_PORT: ${{ github.event.deployment.payload.serial_port }}
         run: |
-          $port = "${{ github.event.deployment.payload.serial_port }}"
-          & "$Env:RUNNER_TOOL_CACHE\arduino-cli\arduino-cli.exe" --config-file config.yaml upload --fqbn arduino:avr:uno --port $port --input-dir build
+          if ($env:SERIAL_PORT -notmatch '^COM\d+$') {
+            Write-Error "Invalid serial port format: $env:SERIAL_PORT"
+            exit 1
+          }
+          & "$Env:RUNNER_TOOL_CACHE\arduino-cli\arduino-cli.exe" --config-file config.yaml upload --fqbn arduino:avr:uno --port $env:SERIAL_PORT --input-dir build